[TimH]

I keep hearing about forged and cast receivers. Whats the difference & which one is better? Don't they also mill receivers also? Thnaks Tim

[Handy]

Milling is what you do with the piece of metal once you have forged or cast it.

Forged is supposed to be better, but sometimes some castings are more consistent dimensionally.

For some things, like AR receivers, it doesn't matter. For other types of receivers and small parts like hammers, cast is a little soft.

[TimH]

Thansk Handy! I'm familiar witht he milling process but I wasn't sure if they made receivers by milling a piece of raw material or what the whole process was. So when they forge a receiver do they heat up the material then kind of press it into the shape they want then preform secondary milling operations? Tim

[telewinz]

Cast vs forged is a very iffy issue. A forging is almost always more expensive because it's labor intensive and time consuming but the forging process is not always without it's limitations. A casting tends to be more "uniform' in its composition and goes through fewer processes to reach its final stage, less chance for error. Also their are certain alloys (and their desirable properties) that cannot go through the forging process well if at all. If a manufacturer is willing to pay the money, their is little to be gained from a forging that can't be equalled or bettered by a casting. For years I worked with cast steel products that would routinely exceed 110,000 psi, they replaced the forged products that were only rated at 75,000 psi and they did it cheaper and faster. Its called science and progress.

[Frohickey]

Definitions...

Forging (http://www.efunda.com/processes/metal_processing/Forging.cfm)

Casting (http://www.acipco.com/centrifugal/casting/index.cfm)


Milling is a machining operation that can be done to both.

[Jim K]

Machining is not only done (usually must be done) to both cast and forged receivers but they can also be machined out of steel stock (commonly called "bar stock", though it can be in forms other than bars). For example, the Pre-64 Winchester Model 70 receiver was machined ("milled") from bar stock; the Post-64 receiver, which some people think is cast, is actually forged.

The Remington 700 receiver is machined from round bar stock, while all Ruger receivers/frames are cast, with the exception of the .22 autos which use either polymer (.22/45) or stamped steel grip frames and heavy wall tubular steel receivers.

Some castings may be as strong or stronger than forged parts, but Ruger revolver frames are thicker than in the equivalent areas of S&W or Colt frames. Ruger, one of the top casting producers in the world, apparently thinks the extra thickness is needed.

Jim

[telewinz]

One of the reasons Ruger's have their "rounded" designs is that they use ceramic molds for their casting process and that design is the best for casting. Ease of mass production (and lower costs) have been a trademark Of Ruger from their beginning. Even the Ruger .22 pistol 1st made back in the 50's (?) was a tech leader by making the frame (stamping) in TWO pieces and welding the 2 halves together. Straight out of the mold, Rugers require little to no machining before assembly. Bill Ruger's contribution to firearms developement and the manufacturing process in general rivals that of Browning or Garand. I am not fond of Ruger firearms other than their 10/22 but you have to admit, the man was a genius and willing to take a risk. Very rare attibutes these days.

[TimH]

Lotsa good info. Thanks Tim

[BHP9]

If a manufacturer is willing to pay the money, their is little to be gained from a forging that can't be equalled or bettered by a casting. For years I worked with cast steel products that would routinely exceed 110,000 psi, they replaced the forged products that were only rated at 75,000 psi and they did it cheaper and faster. Its called science and progress.


Any casting that I have seen that was stronger than a forging was due to the fact that is was given a higher heat treatment and made thicker. When comparing apples to apples there is no casting made that I am aware of that is anywhere near the equal of a good forging.

In industrial catalogs the same thickness and heat treated forging is rated at 2 1/2 times the strength of a casting if both are the same thickness and both have the same heat treatment.

In the past I have had nothing but nothing but trouble with castings as used in firearms. The latest scourge of the gun industry is the dreaded MIM casting that has proven to be very brittle and has an extremely high failure rate.

I have found castings often shatter when subjected to sudden impact, unlike forgings that can be made hard on the outside and softer on the inside to take a lot of pounding and stress. All the castings I have seen are the same hardness all the way through.

Extreme cold seems to make some castings even more brittle than the are by nature.

If there are top quality castings the gun industry certainly isn't using them and as I have said the latest use of the MIM castings has been a real scourge on the gun owners that get stuck with such sub-standard parts. Most throw them away and pay big bucks replacing them with custom made forged parts.

The forging can be made much thinner and lighter than the casting and still be as strong as the much thicker casting. Smith & Wesson themselves advertised this about 25 years ago when they got into a big row with Bill Ruger. Since that time of course time has marched on and now Smith seems to make nothing but castings and is reported to be the one that supplies all the MIM cast internal parts for Kimber ( which have had a very high failure rate). The frames and slides are supplied by Caspian and are reportedly made from bar stock. Most of the internal parts on Smith Revolvers are now MIM and no hand fitting or machining is done on them. I have read on the net that on the Smith & Wesson forum everyone is screeming about the poor trigger pulls of new Smith Revolvers and the pedestrian accuracy of their new revolvers compared to the older quality pieces of not so long ago.

I have had an M1a recieiver stretch that was made of a casting with only 200 rounds fired out of the weapon. I have read on the net and seen pictures of many of the new M1a's suffering a high failure rate with the internal parts that are now castings instead of the forged G.I. parts that were once supplied with their weapons.

I have had a cast op-rod break on an Iver-Johnson M1 carbine that had only 500 rounds fired through it, and when it was replaced by a G.I. forged op-rod the gun never had any further problems with cracking an op-rod.

I have seen parts like automotive bell housings crack when dropped only a few feet onto a concreate floor and in contrast I have seen forged automobile parts hit the concreate so hard they bounced 3 foot into the air an suffer no damage.

I once dropped a H&R revolver on a soft pine wooden floor and the cheap cast rear sight broke right off and in contrast I have seen revolvers and automatics with forged rear sights dropped onto concrete floors and only suffer minor scratches.

Cast parts also just plain look hideous because of their porosity (air holes).

Cast parts rust much faster than forged parts. I recently examined a cast Rossi pump .22 that had a rust hole eaten right through the reciever. I have never seen this happen with a forged reciever. As a matter of fact that day I looked at some Mauser Broomhandle pistols that came from China and were at least 85 years old and probably never had a drop of oil put on them. They had light rust but no severe damage like the rust hole in the Rossi receiver that by the way was only a few years old.

The big myth is that when Gun companies use sub-standard parts it keeps the price of the weapon down so that it is still afforadable to the consumer. Again nothing but propaganda. The real truth is that the gun compaines push the prices as high as the market will bear and by using cast parts, stamped sheet metal and plastic they make astronomically higher profits while still keeping the price as high as possible. They could very well make the same weapon of quality forgings but it would cut too much into their profits and of course any handworkmanship is defintely verbotten because it too would cut to much into their profits. For example even the gun rags are now letting the truth out. The Browning and FN High Powers which were once known for their outstanding accuracy now give 3 inch groups and larger because there is no hand fitting of the barrel to the slide anymore.

In the old days gun companies were family owned and pride in their product in regards to quality workmanship and quality materials were paramont. Today with most of the Gun companies being corporate owned the managers must show a profit to the stockholders and the quality of the product is not even considered because it is well known that all the compaines are pretty much in the same racket of making a product as cheeply as possible to maximize the profits. So there is not much competition from any other compaines that are willing to make less profit but put out a quality product.

All this is why the custom built handgun has become such a big and booming buisness. People know that when buying the factory mass produced product that they are not getting a quality product like they came to expect not so long ago.

I'll pass on anything made of castings if I can help it. And I am not fond of plastic and sheet metal either. I have owned the best of the older made weapons and I am under no illusion in regards to the quality of weapons made of castings, plastic or sheet metal.

[scotjute]

Forging really becomes desirous when the piece involved is under a lot of stress. Some very typical examples that come to mind would be swords, hammers, axes, knifes, etc.
In addition improper heat treatment can ruin an otherwise excellent forging, while proper heat treatment can improve a casting's properties.
Typically with proper techniques and heat treatment, a cast receiver should perform as well as a forged one. SPECIALLY if the casting is done by a REPUTABLE company vs some anonymus no-name firm.

[Detritus]

all Ruger receivers/frames are cast

you missed two, the P95 and P97 also use a polymer frame.


also have to say, crappy is crappy. as in a crappy casting is mroe trouble than it's worth, but then again so is a crappy forging. adn lately both have bene seeing daylight WAY to often.

[gun-fucious]

the broken olympic cast reciever pix
i have seen have jaded me towards any cast AR upper

[curt]

TimH i'd go with what handy said. There is no pratical difference between a quality cast lower and a quality forged lower. The only difference that you might notice is that some of the castings have a greyer looking finish that is slightly rougher to the touch.

It always kills me when i see someone talk about the fit and finish of one AR brand compared to the other and how people will fret over getting their lowers color to perfectly match the uppers...but thats just me i quess.

[AZ Jeff]

BHP9 made a bunch of statements above, far too many to reiterate individually. Suffice to say that they were VERY GENERAL in their nature, and although he had some good anecdotal stories about castings cracking, rusting, etc., they reminded me of the tales of woe we here out of the anti-gunners each time they trot out a sob story as a reason to not allow guns in the hands of the general public.

The fact is that comparing poor grade castings to good grade forgings yields no better results than comparing the inverse.

GOOD GRADE CASTINGS (like those used by Ruger) can be just as functional in ALL ASPECTS as those parts made by forging.

For those of you who disagree, I ask only one question:

Guess what process is used to make a fair number of highly stressed parts used in gas turbine engines? Hint: Ruger has been involved in this business.

[telewinz]

If a forging or casting fails you need to know about the properties of the forging or casting and the cause before making a judgement (most posts I've seen offer NO evidence, just broad based opinions) their are 1/2 dozen casting processes, the manufacturer must select which process and "alloy mix" he can afford or does he wish to cut corners to reduce expenses? (most often the case for "failure"). Again, their are many alloys (with special/desirable properties) available to the casting process that cannot be used in the forging process. Its a very broad statement to say one process is better than another. Needless to say the casting process is and has been a great success in the firearms industry. Casting due to its flexibility and lower costs will only continue to grow while the forging process continues decline. I must admit the cast ALUMINUM (forged would make a difference?) receiver for some of the G3 clones sold by Century Arms were a bit much. There outside diameter was very much oversized compared to any steel receiver. This doesn't seem to be the case with the cast steel receivers used in the Garands and M14's (M1A's). Don't assume because its a forging it's better and don't assume because it's a casting its inferior. Do the research and ask, "what type of alloyed steel was used and what standard was followed".

BTW they also cast the rocket tubes for space craft.

[Jim K]

FWIW, MIM (Metal Injection Molding) is not casting in the normal sense. The processes are completely different. Like castings, though, MIM parts can be of good quality or poor quality. They can also be machined as necessary. Again, like castings, polymer, plastic, light alloys, etc., MIM parts are OK in the right applications. Part of the trouble has been that many gun makers do not have quality engineering and use the wrong materials or use them in inappropriate applications. (An "engineer" I spoke with at one of the major makers of 1911 type pistols didn't even know what a recoil spring plug was.)

The jury is out on S&W use of MIM, but some of the stuff I have seen on the "net" seems to be, to put it bluntly, lies by those who still hate S&W for their past sins. Absurd claims that 90% of all S&W triggers break, or that MIM parts cause inaccuracy, are not worth bothering with.

Jim

[JohnKSa]

One thing that gets missed.

Ruger designed all his guns around his manufacturing methods. Knowing he was going to cast the parts, he designed them to function well as cast parts. And, as pointed out, Ruger is an industry leader in metal casting.

The problem comes when a company decides to save money by replacing a forged part with a cast part. Maybe it works well, maybe it doesn't. If the quality of the casting isn't top-notch, that just makes the situation worse.

What I'm getting at is that using Ruger as an example that cast is just as strong as forged isn't really kosher. His designs were formulated from the ground up around the casting technology available--and being a leader in the field of investment casting, he was fully aware of the limitations of the technology and didn't exceed it. That DOESN'T mean that you can, in general, replace a forged part with a cast part and expect good results. That applies to even top-quality cast parts.

[telewinz]

I accept JohnKSa's view. He hit it right on the head. No one process is perfect and forgings do and probably will have their place for some time in the firearms business, how long is anyone's guess. Older THR's will remember the raised eyebrows at the aluminum receiver of the M16 way back when. Who would have thought 20 years ago that their would be "plastic" receivers for anything beyond a .22lr? Can't be done...... until it is.

[Art Eatman]

This sort of statement, "If there are top quality castings the gun industry certainly isn't using them..." certainly detracts from the credibility of a post. If the writer is wrong in one part, can he then possibly be somewhat in error, elsewhere?

I don't know about "the gun industry" as a whole, but I'd accept that some do less than adequately in their castings. The majority, however, seem to be doing just fine. Ruger is of course the leading example in quality castings. The 77 series have done just fine for decades, and Super Blackhawks have been known to take more abuse than other pistols in .44 Maggie...

Me? I sorta prefer forged, blued steel and good walnut stocks. :D

Art

[hubel458]

They use right alloys and heat treatment on #1's and 77's.
The flat side of a 77 is not any thicker than Rem.Win,whatever,
but I know it will handle more than those.I accidently put a
150,000 psi load through my 77, in the process of developing
my 458 wildcat.Ruined Brass,blewprimer, bulged chamber ahead
of reciever, barrel removed with lathe,checked,rebarreled,
and fired 900 more rounds.castings with right alloys can be made
stronger than forgings as long as heat treated right.Lot of
castings folks have trouble with are using poor alloys.Ed.

[HankB]

From everything I've read, MIM parts, made with the best available process and appropriate materials, are adequate for their intended purpose, usually internal lockwork of various firearms. Note use of the word "adequate" - I've never heard they're as good as, let alone better, than top quality forged and machined parts.

As for casting, I note that today's Browning HP pistols use cast frames, which are considered to be stronger than older forged frames. Alloy and heat treatment are just as important - probably more important - than whether a part is cast or forged.

[BHP9]

As for casting, I note that today's Browning HP pistols use cast frames, which are considered to be stronger than older forged frames

I have read this same statement many , many times and it only proves how good the Factories are in braninwashing the unsuspecting customer.

The real truth is that the new Brownings are heat treated harder than the old forged frames. Now if the old forged frames are given the same heat treatment and thicknes they are still 2 1/2 times stornger than any inferior casting could ever be.

There can be no argument in the cast v/s forged. If given the same quality heat treatment and thickness the forged beats out the cheap cast part or frame completely.

[Don Gwinn]

BHP9, it's interesting that you haven't seen a casting that was stronger than a forging in its intended role with similar dimensions and heat treat, but Telewinz has. So have I.

Each type has its strengths, but for most applications, cast vs. forged is a red herring. Heat treat and geometry are much more important for MOST applications. How you conclude that this means forgings are superior, however, is a mystery to me.

[Art Eatman]

There are just too many variables in forging and in casting for anybody to make grand sweeping generalities about "good" or "bad".

Important factors include the yield strength and the hardness. These are controlled by the alloying and heat treatment. You can goof on a forging as easily as a casting.

Do it right, and a forging will serve just as well as a casting, and vice versa. Do it wrong, and neither is worth a hoot.

Ruger proved castings can work just fine. So did Ford and GM and a host of others, with cast cranks, rods, rings and pistons.

:), Art

[hubel458]

BHP9-- If the alloy is not cheap, the cast and properly treated
receiver is stronger than forgings or machined from billets..They can get better. stronger alloys in precision castings, than can be put in forgings for the same receivers,
because the forging or billets with the toughest alloys are to hard to machine.But can be cast to dimensions needing only a little grinding and polishing.
So the term 'cheap casting' in Rugers case only means a lot of labor and tooling was saved.But they have the most expensive and toughest alloys.Ruger is making receivers
for others like Montana Rifle Co, one a big bore action for
600NE, 585 Nyati, T-Rex, etc.Ed.

[JohnKSa]

There's a lot of apples & oranges on this thread...

Here are some generalities for when comparing similar quality cast and forged parts. That includes similar alloys and proper heat treatment.

Forged parts are going to be springier (more resilient) than cast parts. Therefore, things like hammers and firing pins that take a lot of impact type wear are NOT good parts to make from castings. Neither are things that are expected to flex during normal operation.

Cast parts CAN be harder depending on the heat treat and alloy. So, it's possible to have a "stronger" (harder) cast receiver than a comparably sized forged receiver.

But...

Cast parts tend to fail spectacularly when they break. That's because they don't have a lot of grain and when they break, they tend to go into lots of pieces.

Forged parts stretch and split when they fail, but their grain structure tends to keep them from shattering.

[Handy]

Regardless of what a bolt receiver "should" be made of, some applications just don't matter.

If I was picking an AR receiver, I would go with cast, because it's cheaper than forged, and stronger than plastic. (Hint, if you can make an identical part of plastic, basic cast aluminum is going to be fine.)

[harrydog]

From everything I've read, (and I've done quite a bit of research on this subject because it interests me) cast steel alloys never have the ultimate tensile strength or yield strength of a quality forged or barstock equivalent. Forgings and even barstock (since it is hot or cold rolled) will have a more dense grain structure than a cast piece.
But that doesn't mean a good cast part can't be made strong enough for certain applications. If the design is correct for the application, there will be no problems. The real advantage is that a cast part is cheaper to manufacture. The casting is much closer to the final shape than a forging or obviously a piece of barstock, so only minimal machining is required.
A pistol frame, for example, is not really a highly stressed part, and therefore castings will work well in that application, if they're made properly.
Probably the most highly stressed part in an engine is the crankshaft. Many cranks are made from nodular cast iron and are strong enough for the application. But in a high performance, high rpm racing engine, you'll never see a cast crank. It just wouldn't take the stress. Same thing applies to pistons and connecting rods. The engine block is not a highly stressed part and therefore an iron or aluminum casting makes perfect sense.
Cast parts can be made to be plenty strong enough for certain applications but there are some applications where a cast part, regardless of how good it is, just isn't up to the task.

[Art Eatman]

harrydog, you're absolutely correct. My own point remains that grandiose, all-inclusive generalities aren't helpful in a discussion such as this.

Art

[mohican]

When BHP9 compares a cast bell housing to a forged connecting rod or crank, its an apples to oranges comparisons. The Connecting rods and cranks are much thicker material, made of high grade materials such as 5140. The bell housing might be cast iron, but it is more likely an aluminum alloy.

With todays casting technology, including pressure and vacuum casting techniques, porosity can be eliminated. Corrosion is due to the alloy used as much as the manufacturing method. Corrosion has not been an issue with my blued ruger SBH.

You don't think that casting leads to more competative prices?

how about a comparison between Super Redhawk and Smith 629 prices. Or a comparison between GP100 and Smith 686 prices.

There are places where forged is better than cast, but few examples are true in the civilian gun market.

[Boston T. Party]

Howdy all,

I looked into this issue pretty thoroughly for my new book
Safari Dreams: A Practical Guide To Your Hunt In Africa.

by Kenneth Royce
ISBN 1-888766-09-3
5.5"x8.5" softcover
352 pages, with 100 color photos
shipping in January 2008
$30 + $5 s&h (cash or M.O. only)

Javelin Press
POB 31
Ignacio, Co. 81137-0031


Here are some excerpts from the 5 pages generously contributed
by renowned knifemaker and gunsmith Kevin McClung of Mad Dog
Knives and MD Labs. He knows more about steel, heat treating, etc.
than anyone else of my acquaintance.

I think his remarks bear serious consideration.

Regards,

Boston
http://www.javelinpress.com (Boston's books)
http://www.freestatewyoming.org (FSW website)
http://www.fundamentalsoffreedom.com/fswforum/index.php (FSW forum open to all)
wyoming_freestate@yahoo.com


A Few Words about
Cast Steel Rifle Receivers

by Kevin McClung
MD Labs Senior Engineer
Copyright 15 January 2007. All Rights Reserved.

My good friend Ken Royce has asked me to add my two cents regarding the "cast receiver" issue. Profligate spender that I am, he is getting far more than two cents worth. The subject merits no less, as it relates to the safety and survivability of the dangerous game hunter.

The thesis here is that cast steel receivers are inherently less desirable in a Dangerous Game Rifle (DGR) than a properly heat treated forged billet machined steel receiver. Why? Because the cast receivers are not as durable or reliable due to the process they are created with: Vacuum Casting.

In a DGR, reliability is everything.

The problem with cast high carbon steel (as opposed to cast titanium or aluminum alloy) is that the carbides precipitate in dendrites, rather than being evenly distributed throughout the steel as in forged material. The forging distributes the carbides properly and homogeneously, and develops suitable grain structure and direction, rather than the amorphous matrix and dendritic crystalline structures found in cast steel.

The problem here is that to derive suitable strength without adding unnecessary bulk, the carbides must be evenly distributed throughout the steel. Carbide dendrites have the problem of making a fernlike lattice of extremely hard and very brittle material in the matrix of the alloy. As a result the knives, receivers or other items made this way tend to have very low modulus numbers. In other words, they lack springiness despite the soft, spongy nature of the matrix of metal alloy surrounding the dendrites.

When these carbides precipitate out into veins (dendrites) each of them becomes a potential fracture line in the steel.

They have the dubious advantage of adding a "saw tooth" type structure to the steel at the edge of cast steel knives, but the ability of the steel to withstand any wear, shock, prying, or other robust usage goes out the window. Carbide dendrites are built in failure paths. The dendrites are considerably more brittle than the surrounding steel, and offer a fernlike failure path for stresses to propagate brittle stress cracks.

Material properties of steel vs. titanium is an apples and oranges comparison, perhaps even an apple and potato type comparison. Titanium and carbon steel are as different in basic properties as any two metals can be. Despite their tendency to produce homogeneous structures during casting, even (vacuum) cast titanium and aluminum alloy structures require suitable heat treat to assure the desired properties are developed after casting.

Fact: The cast receiver manufacturers use vacuum casting. Vacuum does not align grain structure, so far as the metallurgy goes. Neither vacuum nor centrifugal casting distributes carbides properly.

Fact: Forging does align grain structure and properly distributes the carbides in the alloy.

Fact: Casting carbon steel and martensitic stainless produces carbide dendrites. These dendrites weaken the structure (as compared to a forged structure) by precipitating carbides in a fernlike lattice.

Fact: Casting steel is merely a way to save time and money in obtaining a net or near net shape. Its sole benefit is LOW COST to net shape. The penalty for the cost saving is less strength, ounce per ounce, than a forged part.

Fact: Serious high performance applications require that cast steel ingots are roll forged to sheet, plate or billet; or are hammer forged to near net shape after casting to develop ultimate attributes for a given alloy. This is true in everything from mild steel used in car bodies to structural steel used in aircraft and automatic weapons. Manufacturers of cast receivers skip all of that troublesome "middle part" where the best attributes are developed.

Fact: This is not to say that investment cast frames and parts are not adequate for many functions, even in weaponry. But, merely "adequate" in the eyes of the manufacturer is often less than wholly desirable for the end user who may be betting his life on the gear.

It is simply my choice to use a superior part with superior attributes of strength and durability, especially when they are commonly available at competitive prices.

I would also point out that were investment casting high strength steel to net shape a desirable method of making a truly superior firearm, this process has been available for over 200 years now and has never once been used to produce an American military shoulder firearm of significant caliber, nor has it been applied with notable success to high strength cutlery or edged tools.

There are many cast steel axes available, and they are invariably inferior to forged axes of identical pattern. Even Krupp's famous cast Stahl was subsequently hammer or roll forged to obtain best attributes.

Ruger's steel castings are not, in my opinion, better or worse than any other steel casting used in firearms. They are, however, inherently weaker, ounce per ounce, than forged steel receivers of proper construction and heat treat.


(Royce Note: Since market prices of forged steel receiver rifles are not any higher than cast steel receiver rifles, there is no monetary incentive to choosing cast steel. Thus, what incentive remains at all?)

[JesseL]

Boston T. Party:

Interesting write up, but can you or Mr. McClung point to any examples of a Ruger receiver failing in circumstances that would have been survivable by a forged product of similar price or weight? IMHO real world testing trumps speculation and theoretical analysis every time.

[daniel (australia)]

Here are some excerpts from the 5 pages generously contributed
by renowned knifemaker and gunsmith Kevin McClung of Mad Dog
Knives and MD Labs. He knows more about steel, heat treating, etc.
than anyone else of my acquaintance.

I think his remarks bear serious consideration.

Much of what he has said merits serious criticism, if not outright rejection. His overall thesis, that ...cast receivers are not as durable or reliable due to the process they are created with: Vacuum Casting. is nonsense.

The problem with cast high carbon steel (as opposed to cast titanium or aluminum alloy) is that the carbides precipitate in dendrites, rather than being evenly distributed throughout the steel as in forged material. The forging distributes the carbides properly and homogeneously, and develops suitable grain structure and direction, rather than the amorphous matrix and dendritic crystalline structures found in cast steel.


Rifle receivers are not made from high carbon steel. Instead they are usually nowadays made from a medium carbon CrMo alloy, such as 4140, or from a martensitic stainless like 416, which is fairly low in carbon (<0.15% C). Older receivers were typically made of plain carbon steel either of medium carbon content, or low carbon with a carburised surface.

Why is that important? well, for starters the fact that the author started out with an error like this sends the whole argument down the wrong road. You see, with the steels actually used (known as hypoeutectoid) it is the ferrite which starts to solidify first as the steel cools from liquid, not the carbides. You don't get dendrites of carbide at all. Further, as-cast steel doesn't have an amorphous structure (if it did it would be glass:rolleyes:), nor is dendritic segregation going to be seen in any finished casting - especially after heat treatment, any more than forging is going to "distribute carbides":rolleyes:.

The principal advantage of forging is that if you take this as cast structure and hammer it into shape you close up any porosity and align any inclusions - it is these which give the so-called fibre structure. You also increase the number of dislocations in the crystal structure and, if you then heat treat, this helps refine the grain size. The as heat-treated grains aren't "aligned" though, only the inclusions, and with clean modern steel this is much less a factor.

Now with castings the principal issues of the past were such things as shrinkage, cracking and inclusions (whether solid or gaseous) weakening the structure. However with good clean steel and modern casting technology, and a product designed to be cast you can eliminate these problems, and alloy additions can serve to refine the grain structure, meaning the end product can be just as durable if not more so than a forging.

Fact: The cast receiver manufacturers use vacuum casting. Vacuum does not align grain structure, so far as the metallurgy goes. Neither vacuum nor centrifugal casting distributes carbides properly.
There's three "facts", or rather assertions there, actually. Vacuum casting is one technique, where air pressure is used to drive the liquid metal into an evacuated mould. As I understand it this is not the method actually used however. Ruger for example uses investment casting. This can be done by melting and pouring the metal in a vacuum chamber (for removal of gases and to assure purity, for really high-duty results - the usual method for Ti alloys), but is more usually done in air.

Casting actually can align grain structure, for good or ill, by virtue of the design of the gates and risers and the use of chills. Generally speaking though what is actually wanted is a fine grain structure, which is produced in forgings by the creation of dislocations to nucleate grains on recrystallisation, and in the case of castings largely by the use of good design and/or grain-refining alloy elements.

As for "distributing carbides properly" well, it is hard to make any sense of that assertion at all. the distribution of carbides is a product of grain size, and to some degree heat treatment.

Fact: Forging does align grain structure and properly distributes the carbides in the alloy.

No, forging aligns non-metallic inclusions not grain structure. If you eliminate the inclusions with a clean steel the point is moot. It is also a method of grain refinement, but the product is fine, randomly-oriented spherical grains.

Fact: Casting carbon steel and martensitic stainless produces carbide dendrites. These dendrites weaken the structure (as compared to a forged structure) by precipitating carbides in a fernlike lattice.

This is nonsense, particularly in view of the fact that we are talking about hypoeutectoid steels where it is the low-carbon ferrite which solidifies (precipitates) first.

Fact: Casting steel is merely a way to save time and money in obtaining a net or near net shape. Its sole benefit is LOW COST to net shape. The penalty for the cost saving is less strength, ounce per ounce, than a forged part.

Casting does enable savings in cost. That isn't necessarily a bad thing. It also allows the production of shapes which forging cannot, among other things. It is not true however that castings are necessarily less strong than forgings.

Fact: Serious high performance applications require that cast steel ingots are roll forged to sheet, plate or billet; or are hammer forged to near net shape after casting to develop ultimate attributes for a given alloy. This is true in everything from mild steel used in car bodies to structural steel used in aircraft and automatic weapons. Manufacturers of cast receivers skip all of that troublesome "middle part" where the best attributes are developed.


That was probably true up until a few decades ago. Nowadays very high duty components are indeed cast, because in some cases that is the best technique for developing the properties needed. Turbine impeller blades are a good example. Another I've been involved in is the production of handcuff components: the little chain between the handcuff wristlets being cast in one unit so as to eliminate any welds or joins in the links which might weaken the links.

Fact: This is not to say that investment cast frames and parts are not adequate for many functions, even in weaponry. But, merely "adequate" in the eyes of the manufacturer is often less than wholly desirable for the end user who may be betting his life on the gear.


I would rather stake my life on a product which has been properly engineered and tested than anyone's mere assertion myself. It is quite possible to make unreliable equipment with any technique, including forging.

I would also point out that were investment casting high strength steel to net shape a desirable method of making a truly superior firearm, this process has been available for over 200 years now and has never once been used to produce an American military shoulder firearm of significant caliber, nor has it been applied with notable success to high strength cutlery or edged tools.

Probably more to do with the inherent conservatism of military weapons procurement (hey, I've been involved!) and the fact that the current service weapons of your Army were designed so long ago. That isn't a criticism of the weapons either, but just a statement of fact. The M16 platform for example is fundamentally a 1950s design, and it was designed around the production engineering of the time. Investment casting has been around for far longer than 200 years, but as a means of producing high-integrity steel components its history is much shorter. It is becoming a well-proven production method for small arms though.

In the case of edged tools it is also gaining ground. Not perhaps in the area of custom knives - again perhaps a function of innate conservatism and the economic barriers, but is certainly is being used in the production of such items as drill bits for rock drills, shear blades, defibriators, surgical blades (as well as surgical instruments and implants), turbine blades and all sorts of other components.

There's altogether too many myths about casting and forging. Both have their place, and with good design and materials and heat treatment both can be used to make strong reliable components for firearms and other applications.

[hubel458]

Companies making recievers like Ruger use a Cr-Moly alloy
that when done right like Ruger does, and heatreated are
stronger than forgings with heatreatment, by 20 percent.
I bulged a barrel on a Ruger 77 that would have destroyed
any forged or machined billet action. And still using action
today after taking out barrel with lathe.There is no carbon placement
problems in the process with that alloy, with heatreated tensile
strengths way over 200,000 psi possible. Ed

[Boston T. Party]

from JesseL:
Interesting write up, but can you or Mr. McClung point to any examples of a Ruger receiver failing in circumstances that would have been survivable by a forged product of similar price or weight? IMHO real world testing trumps speculation and theoretical analysis every time.

I've not heard of a catastrophic failure of Ruger M77 African rifle receiver.
(Perhaps the extra mass of its receiver is sufficient compensation for
an inherently weaker material. However, I certainly wouldn't want to
experience the first KB.)


McClung did not claim to have heard of one in his essay, either, (nor
did he write that the M77 is prone to catastrophic failure), but
that one takes additional and unnecessary risk with cast steel DG rifle receivers.

Since I can buy a forged-steel CZ550 or Win M70 Classic for
the same (or less) money, I choose forged-steel as it hasn't the
issue "built-in failure paths" (however theoretical such may seem
to some).

I have heard of a Ruger .45 Colt cylinder letting go, and the owner's
explanation of a double powder charge seemed untenable given
that a single charge of his published load was nearly compressed
to begin with (hence he could have doubled charged the case).

The pictures were inconclusive; i.e., I couldn't tell if the cylinder
had any voids in the metal.

____________
daniel (australia), thanks for the lengthy post.

I'm not technically competent to reply, but Kevin is and perhaps he will.

Boston

http://www.javelinpress.com (Boston's books)
http://www.freestatewyoming.org (FSW website)
http://www.fundamentalsoffreedom.com/fswforum/index.php (FSW forum open to all)

[SlamFire1]

Further, as-cast steel doesn't have an amorphous structure (if it did it would be glass), nor is dendritic segregation going to be seen in any finished casting - especially after heat treatment, any more than forging is going to "distribute carbides".

The principal advantage of forging is that if you take this as cast structure and hammer it into shape you close up any porosity and align any inclusions - it is these which give the so-called fibre structure. You also increase the number of dislocations in the crystal structure and, if you then heat treat, this helps refine the grain size. The as heat-treated grains aren't "aligned" though, only the inclusions, and with clean modern steel this is much less a factor.

Daniel, good post and I learned something from it. But I am still confused about grain alignment and material properties.

I read in "Casting Handbook" that Forgings have directionality of properties, similar to the way wood is strong with the grain and weak against the grain. There are no directional variations in cast steel and therefore the mechanical properties are uniform in all directions. According to the handbook casting properties are in-between the high and the low for a forged part of the same material. The handbook also stated that forging are superior in endurance or fatigue life in the direction of the “grain”, but are inferior across the grain. Casting properties were given as unidirectional.

I guess that means if the part is designed with the grain in the proper direction, a forging would have superior material properties. So what does heat treatment do to this? Does heat treatment remove this directionality of properties, or make it insignificant? Or does this only apply in terms of high carbon steel, not alloys like 4140?

[Horsemany]

I have noticed several desireable features about the Ruger 77 castings and other Rugers. Ruger spins their castings in a centrifuge as the are filled with steel to improve density. Ruger receivers are Rockwell hardness of Mid 50s to 60. Forged receivers are typically in the 20's Rockwell from what I've found. This allows Ruger to use one piece stainless bolts and not have galling issues. Mine has been used hard for 10 years and has approximately 1000 rnds through it and the bluing isn't even worn off the bolt raceways. And I recently noticed something interesting about the integral ring dovetails. I have had the rings on and off a dozen times or more and the sharp edge of the dovetail is pristine. The bluing is still perfect even. This would not be the case with softer forged steels. My gunsmith also told me he couldn't put a scope base on my GP100 because it was so hard he couldn't tap it properly. I am not claiming Rugers are flawless, but I do not think the fact that they are cast makes them inferior to my other guns which cost several times more.

Also I have something to add in regards to quality forgings. I work in the manufacturing field. We use Craftsmen forged 5/8" open end wrenches to tighten jigs for fabricated roof trusses. The brackets are tightened by tapping on the back of the wrenches with a hammer. Many of the wrenches will last several months with this type of abuse. Most are so beat up the edges of the wrenches have flat lips from the hammering. But some of the wrenches will crack after only a few hours of use. It is my job to make exchanges and supply new wrenches when needed. Most of the wrenches that break prematurely have a grain structure and the steel breaks on that grain. In the forged wrench world I can tell you that the failure rate is around 1 in 10. It's been that way for years so it's not just a fluke. We go through hundreds per year. I'm not sure how this relates to firearms mfg. but I thought it might be helpful to acknowledge that forging steel is not always a perfect science. Just as the quality of castings can vary so can forging.

[scotjute]

SlamFire1,
The purpose of the heat treatment (post heat treatment) is to relieve the excessive stresses in the forged piece. This restores a certain amount of ductility to the piece. Too much heat treatment would eventually undo most of the benefits done by the forging process. Too little and the part might be brittle. Correct heat treatment is very critical to achieving the optimal properties of the steel. A plain carbon steel knife blade properly heat-treated is normally preferably to an expensive alloy steel blade with poor heat treatment. Without proper heat treatment, the full potential of a piece of steel (whether from forging, alloying, etc)will not be realized.

[skinewmexico]

It's all fun until someone picks on someone's favorite brand, then it's "get out the textbooks"! Kool-Aid at 5!

[Dobe]

I found this also interesting in the forge vs. cast. Look under HisSoldier, next to the last post on this page.

http://www.thehighroad.org/showthread.php?t=326256

[daniel (australia)]

Daniel, good post and I learned something from it..

Thanks mate. You’ve also asked some excellent questions.

… But I am still confused about grain alignment and material properties.

I read in "Casting Handbook" that Forgings have directionality of properties, similar to the way wood is strong with the grain and weak against the grain.

It is important to point out that “forging” is done hot – ie above the recrystallisation temperature of the metal. If we were to deform the metal cold the grains would indeed be deformed and elongated in the direction of metal flow. The properties in such a cold-worked structure are quite directional and the metal typically strain hardens to a considerable degree. We see this with brass cartridge cases, which are cold drawn.

If the metal is deformed hot however (or subsequently heated above the recrystallisation temperature) then recrystallisation occurs, with the deformed grains replaced by new strain-free spheroidal grains. Indeed the dislocations in the crystal structure produced by the deformation act as nucleation sites for new undeformed grains to grow, so forging (or cold work followed by heating) acts to refine grin structure.

Why then do forgings have directional properties? Well the answer is largely in the impurities/inclusions in the metal. Straight out of the mill inclusions tend to form around grain boundaries, creating weaknesses. Forging tends to line them up with the direction of deformation.

If we imagine forging a sword for example you’d be lining them up along the blade. This means that they are not there to facilitate the propagation of a crack across the long axis of the blade, and in fact act to interrupt the growth of such a crack. The inclusions may however act to facilitate splitting along the length of the sword, but we’d hope to avoid the imposition of a load which would do that. In the case of a wrench or spanner we’d aim to have them flow along the handle and around the crescent

http://hsc.csu.edu.au/engineering_studies/transport/3058/images/figure4.gif

as opposed to what you’d get if you machined from bar stock:

http://hsc.csu.edu.au/engineering_studies/transport/3058/images/figure5.gif

Of course, the cleaner the steel the less this is a factor.

There are no directional variations in cast steel and therefore the mechanical properties are uniform in all directions.

That is not necessarily true. With what you might call old-fashioned casting technology you typically have small grains at the surface but long columnar grains growing away from the casting surface into the body as the casting cooled. Shrinkage and cracking also would often be found (and ideally repaired before the casting was finished). All of this could lead to some lack of uniformity of properties, and it is this sort of casting that many people are thinking of when they think of a cast receiver. In fact this used to be the running gag about castings:

Cast’ing n. : product comprised of various proportions of metal, moulding sand, slag and other inclusions, porosity, shrinkage and cracks, more or less held together by welding repairs and ignorance.

This is all a fairly gross oversimplification but techniques have existed for a fair while to eliminate such problems in high-spec. castings.

According to the handbook casting properties are in-between the high and the low for a forged part of the same material. The handbook also stated that forging are superior in endurance or fatigue life in the direction of the “grain”, but are inferior across the grain. Casting properties were given as unidirectional.
To some degree this is the crux of the argument. The thing about forging is that by giving the steel (which originated as a casting) a good bashing you’d close up all the voids, line up all the inclusions, refine the grain and end up with a reliable part. Fatigue resistance and for that matter shock or impact resistance were thereby improved, as the cracks, voids, and inclusions which serve to initiate and/or propagate failure were eliminated.

Now with a good clean steel, the right alloy additions and casting technology you can produce a casting which can have the same properties, by making it without the cracks, voids and inclusions in the first place.

[daniel (australia)]

Horsemany

50-60 on which Rockwell scale? I'd be pretty surprised if the core hardness was much over 30-35 Rc, but a hard skin is certainly a good way of reducing galling and wear. The old Mauser actions (forged) were carburised to the same effect, with a fairly soft but very tough core surrounded by a thin glass hard case, and that makes them very slick working.

[cracked butt]

Does anyone make centerfire barrels that are cast? If casting is as strong as forging, it would seem that this would be a good way to make them?

[SlamFire1]

Daniel: Many thanks for your reply.

This discussion of forged versus casting is always and interesting one, and because of it, I did my own research, but obviously, you know more.

I think forgings have been an issue for a number of reasons: I think first and foremost because of the lack of decent technical gunwriters in the US.

One standard reference, “Hatcher’s Notebook” is excellent, but dated. General Hatcher’s majority experience with forging and metallurgy dated from 1917. He put out the best information we have on the metals and heat treatments used in US firearms, but the information dates to WWII. General Hatcher died around 1964 and there really has not been a gunwriter with his technical or managerial background in print since then. When the Ordnance writers of his generation died or retired, very little new technical information on firearms has been made to the public. (Stuart Otteson wrote two books on the Bolt Action but that was almost 30 years ago). The modern gunwriter is a guy who knows how to align his sights, pull the trigger and is able to describe the event from a keyboard. And that is as technical as they get in print.

Your statement was right on mark:

“Probably more to do with the inherent conservatism of military weapons procurement (hey, I've been involved!) and the fact that the current service weapons of your Army were designed so long ago. That isn't a criticism of the weapons either, but just a statement of fact.”

The prototype M14 was designed in the late 40’s and tested as the T44 until adoption in 1957. Having just read “The Great Rifle Controversy” by Ezell, I was surprised to find out how much influence the Production Engineers at Springfield had in the decision of what rifle replaced the M1 Garand. They wanted a rifle like the M1 Garand because they were familiar with manufacturing an M1 Garand. They pushed hard to keep the new rifle as similar as possible to the old one. The M1 had forged receivers, the M14 was a forged receiver. Incidentally, I think every firearm built at Springfield Armory, back to the 1873 Trapdoor, was built from forgings.

A large number M14 fans virtually worship forged receivers, have created vast libraries of threads why forged is better than anything thing else, and I think their devotion to the hammer of Vulcan has created a lot of negative information about castings.

If you don’t mind, if I ever get into discussions again with these gentleman, I am going to liberally use the information from your post. You say it so well.

[SwampWolf]

Responses to a thread that is over four years old are just as undetermitive as the original posts were and my take remains the same: though I may prefer forgings because they seem to be intrinsically "stronger", investment castings that are executed well and may make a quality firearm more affordable is a process that benefits the consumer in terms of value. Though a forged Model 70 may well be stronger than an investment cast Model 77 (and I'm not saying it is), in the real world it doesn't make any difference. And, as a side note maybe based on hyperbole, Ruger is still making guns and Winchester isn't.

[Boston T. Party]

For an illustrative comparison, try the modern cast M1 vs. the forged WW2/Korea M1.

I had a cast M1 from SA which began to suffer failures to fire from
light primer strikes. Three different trigger groups times several
different ammo types didn't solve it.

Ron Smith personally examined the rifle and measured receiver stretch.
The M1 gas system is more violent than the M14/M1A's, and a cast receiver
just isn't suitable for a Garand, was his observation.

btw, if there is anybody who is qualified to answer the cast vs. forged
issue regarding rifle receivers, it would be Ron. (I should have mentioned him
in conjunction with Kevin, but Ron is very busy. I'll give him a call and ask
if he's already written something I can include here.)

___________
from cracked butt:
Does anyone make centerfire barrels that are cast? If casting is as strong as forging, it would seem that this would be a good way to make them?

Not rifle barrels, TMK.
Pistol barrels (Ruger), yes.

Is the reason one of strength, or are 16+" long gun barrels
(including shotguns) too long for the casting process?

I'd bet on lesser material strength vs. uncastable part length.

Boston

[cracked butt]

investment castings that are executed well and may make a quality firearm more affordable is a process that benefits the consumer in terms of value.

Though a forged Model 70 may well be stronger than an investment cast Model 77 (and I'm not saying it is), in the real world it doesn't make any difference.

What I don't get is everyone says that Ruger castings are as strong and cheaper, yet Rugers are usually priced as much if not higher than its competitors.
Example: the Ruger M77 is usually priced the same if not more than a Win Model 70. The Ruger MKII/MkIII pistols are far inferior to Sig Trailside pistols and are similarly priced.

Ruger is still making guns and Winchester isn't.
This is true, but FN will start making Winchester Model 70s soon, and Miroku will be or are making winchester leverguns, my guess is that neither will be going with cast receivers?

[SlamFire1]

I'd bet on lesser material strength vs. uncastable part length.

Maybe. But I would bet that the primary reason no one casts barrel blanks is that you can get round bar stock from lots of suppliers.

I don't know if the suppliers get the bar stock direct from the mill, or turn it from extruded pieces. I don't see any reason why a steel mill could not or would not extrude or roll hot steel into round bars. When you think of it, there are a lot of things that start off as a round piece of steel.

[daniel (australia)]

Does anyone make centerfire barrels that are cast? If casting is as strong as forging, it would seem that this would be a good way to make them?

For the ordinary rifle barrel there'd be no advantage. Bar stock is fairly cheap, pumped out in vast tonnages by steel mills. Existing processes, especially the rotary forging machines made by GFM and others pump out good barrels quickly and cheaply. Investment casting comes into its own for complex shapes which would otherwise require a lot of machining - like receivers for example.

That said enormous numbers of barrels of artillery size have been cast over the past several centuries, and there's also such specialist applications as Stellite liners for machine-gun barrels, which are cast to very close to final form because the stuff is so hard to machine. Actually a cast Stellite liner, finished internally by EDM and carbon-fibre wrapped would have to be close to the ultimate, but serious bucks would be required.

I had a cast M1 from SA which began to suffer failures to fire from
light primer strikes. Three different trigger groups times several
different ammo types didn't solve it.

Ron Smith personally examined the rifle and measured receiver stretch.
The M1 gas system is more violent than the M14/M1A's, and a cast receiver
just isn't suitable for a Garand, was his observation.


Stretching indicates the steel was soft, and that almost certainly has nothing to do with whether it was cast or forged. More than likely a heat treatment issue, or perhaps the wrong steel. Do you still have the receiver? It'd be worth checking the hardness, and not just in one place but a few including in the load-bearing areas.

It is also worth noting that the M1/M14 receiver was of course engineered to be forged and machined. You can't necessarily take such a design and blithely make a replica by investment casting - you'd need to consider carefully the way the mould will fill and solidify, and that would require careful consideration of the mould design and perhaps some tweaking of the receiver details for the best results. The better approach of course is to engineer the design for production by casting right from the start, as Ruger and others have done.

All the design and engineering work will be for nought if you don't get the material and heat treatment right though, just as it would be in the case of a forged receiver.

[Kurac]

When Sears Craftsman brand starts advertising that their wrenches are cast then we will know that it is just as good as forged. Maybe turbine blades are cast but you can bet that the hub which holds them all together is not. Yes Bill Ruger was a smart man, thats why his cast frames are quite a bit thicker than the forged frames of his competition. I lost track of how many cast items I have broken in my lifetime but I cannot think of one forged part that I have broke.

[SlamFire1]

Stretching indicates the steel was soft, and that almost certainly has nothing to do with whether it was cast or forged. More than likely a heat treatment issue, or perhaps the wrong steel.

As Daniel has alluded to earlier, proper heat treatment is far more critical than method of fabrication or even material. You can surf knife forums if you want to verify that, you don't get the heat treatment right, the part is not going to handle the loads, or cut the bacon.

Heat treatment is something you don't hear much about, but I have talked to folks in the firearms industry, complicated parts, such as the M1911 slide with thick areas, thin areas, non symmetrical areas, it is easy to get the heat treatment wrong.

And you would be surprised by how much they have to derate the material properties of something that has a weld.

[Kurt_D]

Wow, I'm not reading this whole thread but forgings are stronger than the same sized/shaped casting. I mean really is it that hard to understand?

examples:

Car parts - universally known that forged cranks and pistons (as well as other parts) are stronger than the cheaper cast versions. I'd love to see some of ya'll try to tell some racers, teams, mechanics that cast is better...

Aircraft - once again all critical parts (that are metal) are forged for strength. I guess you guys need to tell Boeing, Lockeed, etc. that their wasting money not using cast parts because heat treating is somehow going to work majic.

In AR15s - search AR15.com, you will find several threads on cracked/broken cast recievers and almost none on forged/billet. I know cast is good enough for 99% of civi use but in this case facts are facts - cast is weaker.

In swords - a hammer forged blade will be stronger than cast one. Yes they both need to be heat treated but the fact remains.

In knives - good ones use steel that is rolled into sheets by high pressure rollers, just like forging uses high pressure blows to shape a product. Of course heat treating is the heart of the blade but a casting will not be as strong as rolled/forged steel.

Yes, there are different alloys and you can change sizes but with all things equal (same alloy/heat treating/size) forged will always be stronger than cast.

[General Geoff]

^^unless there's a part that's shaped in a way as to make forging impossible, but that improves application-specific strength, and can only be fabricated via casting.

[Kurt_D]

true, true.

But then you probably could mill it from rolled billet which should be stronger than cast, if the extra strength is needed. Only problem there is cost goes through the roof.

[General Geoff]

Are billets not cast?

[SwampWolf]

cracked butt: I believe Ruger MkII and MkIII pistols are still being fabricated from "stamped steel", not the investment cast process- and I hardly think they are in any way inferior to Sig "Trailside" pistols.

Concerning the difference in prices between the Ruger M77 Mark II and an equivalent Winchester Model 70; in comparing the two, using each one's 2005 catalog, the Ruger"Standard" model retailed for $716.00 and the Winchester "Classic Sporter III" model retailed for between $778.00 and $810.00 (depending on the caliber). These are the two models from each company that are the closest in features and configuration. In my experience, this disparity in price has always been reflected in "street prices" and the price spread has always favored Ruger. I can't speak for where you shop but, in my neighborhood at least, Ruger has always offered the better "value".

Finally, if Miroku (or some other foreign company) starts making Model 70s again with forged receivers, one has to figure in the cheaper labor costs as part of the equation (in determining which manufacturing process offers the biggest bang for the buck).

[H2O MAN]

I chose forged Chinese receivers for all of my M14s for one reason:

USGI parts fit and function in these receivers better than any other receiver except USGI and the rare SEI receiver.

NOTE: My cast Springfield receiver was a little out of spec in the scope mount stripper clip guide area, but it was fine otherwise.
However, All of the cast reproduction parts failed with less than 400 rounds fired. USGI and some Chinese parts are better.

[daniel (australia)]

Wow, I'm not reading this whole thread but forgings are stronger than the same sized/shaped casting. I mean really is it that hard to understand?

Maybe you should do more reading.


examples:

Car parts - universally known that forged cranks and pistons (as well as other parts) are stronger than the cheaper cast versions. I'd love to see some of ya'll try to tell some racers, teams, mechanics that cast is better...

Well, you aren’t really comparing apples with apples, nor are you looking at the right property in those examples. If we compare a forged steel crankshaft or con-rod with one of conventional spheroidal graphite or nodular cast iron the forged steel will generally be significantly better, at least for racing and high duty. That is not because of strength though but resistance to fatigue failure, which is admittedly much better for forged steel than any cast iron or even the general run of cast steel.

Fatigue is a big factor for cranks and rods, but not rifle receivers: a crank and rods will undergo more load cycles in a few seconds at full noise than a rifle receiver will undergo in its entire service life. That is why as well as specifying a forged crank your tuner will also be obsessive about radiusing all corners, shot peening and polishing, crack testing, and balancing, all to reduce the likelihood of fatigue cracks being initiated. None of this is relevant to rifle receivers.

There are better materials than these for racing car components too, such as Metal Matrix Composites, already seen and then banned from use in F1 pistons. MMCs are generally produced by casting or else powder metallurgy, and have particular advantages for pistons due amongst other things to the thermal loads.

F1 engines do use investment castings in the form of valves, valve-train components, blocks, gearbox housings and a myriad of others. The rules specify a steel crank though, so that is what is used.

Aircraft - once again all critical parts (that are metal) are forged for strength. I guess you guys need to tell Boeing, Lockeed, etc. that their wasting money not using cast parts because heat treating is somehow going to work majic.

Heheh – no need to tell them, they already know:neener:.

In fact about 10 years ago Boeing’s CEO gave an interview which he circulated to the company’s engineers to the effect that they should begin a targeted program to replace forgings, assemblies or fabricated parts with cast components. Among other things he expressed the view that Boeing could achieve a 20-35% reduction in tooling alone by converting a fabricated assembly to a cast component. Boeing has put that approach into effect very successfully.

And Lockheed?

Fort Worth, Texas, July 24th, 1998 -- The Metals Group of the Advanced Affordability Initiative at Lockheed Martin Tactical Aircraft Systems has been evaluating a process to reduce airframe assembly costs, and the early prognosis is good…
…Preliminary cost estimates indicate a savings of 15 to 20 percent over current processes. …
…In addition to the cost savings, investment casting also improves quality because unitized construction can eliminate potential fatigue problems associated with the numerous fastener holes required for assembling detail parts. Moreover, the designer can create shapes that are normally very difficult or impossible to machine. Shapes of this type improve load distribution and ultimate strength.

It used to be the case that cast components in aircraft had to be spec’d with a built in fudge factor on strength, because they were thought to be less strong and reliable (and back then, probably were). That factor is rapidly becoming a thing of the past as it is recognised that a sound casting can indeed be just as strong as a forged one or a fabrication.

As well as being as strong, castings can be developed more quickly and at less cost. They can also be produced with such features as coolant ducting, which can’t easily be done with other techniques, and complex shapes can be produced in one piece saving enormously on assembly time and warehousing complexity. That is why they are forming more and more of the structure of modern aircraft, as well of course as the major components of their engines. Just ask Boeing and Lockeed:p

In AR15s - search AR15.com, you will find several threads on cracked/broken cast recievers and almost none on forged/billet. I know cast is good enough for 99% of civi use but in this case facts are facts - cast is weaker.

I would be surprised if it was solely due to the fact they were cast. As I said earlier, it is perfectly possible to make bad receivers by either casting or forging. Witness the fact that well over a million Springfield 1903 models had heat treatment problems which led to a number of failures and to these low-number receivers being considered less than safe. That doesn’t mean forging is a bad technique, and nor does the alleged failure of some unquantified number of AR15 knock-offs. Can you point to what aspect of their failure is attributable to being cast, and not to poor heat treatment, poor quality control or other factors?

In swords - a hammer forged blade will be stronger than cast one. Yes they both need to be heat treated but the fact remains.

In knives - good ones use steel that is rolled into sheets by high pressure rollers, just like forging uses high pressure blows to shape a product. Of course heat treating is the heart of the blade but a casting will not be as strong as rolled/forged steel.

I doubt that anyone has tried making swords by modern casting methods, but there are indeed knives being made that way, and the best of them have some very good properties. Strength is of course only one property of a good knife. Certain cast cobalt alloys have good strength coupled with excellent wear resistance, good cutting properties and good corrosion resistance. There are also high end cast stainless knives such as the Boye “Dendritic Steel”, as well as more prosaic but also more widespread applications such as surgical blades, shears and so on which are well proven.

Yes, there are different alloys and you can change sizes but with all things equal (same alloy/heat treating/size) forged will always be stronger than cast.

No longer necessarily true, and there are other advantages one process might have over the other including not only the physical properties of the finished article, but time to market, development and tooling and production costs, and even whether you can make it that way at all.

Getting back to rifles though, the well-proven reality is that investment casting is being used, much more widely than just by Ruger. Browning, Sako, Miroku and many others are also using this technique. With proper heat treatment and QA it is well proven as a means of making sound receivers and other firearm parts, just as with proper heat treating and QA forging can be used, or machining from bar or seamless tube stock. There is no longer any technical reason why a receiver made by one method or another, all else being equal, should be any less reliable or durable than another.

[Reyn]

Good post Daniel. Interesting.

[Boston T. Party]

Regarding my cast-steel receiver SA M1, Ron spoke of
the cast steel being the issue vs. the heat-treat.
I no longer have that gun, so we can't test surface
and core hardness.

I understand how important heat treatment is, regardless
of forged vs. cast steel parts.

Ron Smith likes the Chinese M14S forged receivers, but
they are too soft and need to be re-heat-treated (a
service he offers).

__________
from daniel:
For the ordinary rifle barrel there'd be no advantage. Bar stock is fairly cheap, pumped out in vast tonnages by steel mills.... Investment casting comes into its own for complex shapes which would otherwise require a lot of machining - like receivers for example.
I can think of a perfect example:

Ruger's Model 77 Frontier rifle, whose barrel (theoretically) should have
been cast to include an integral forward mount for the Scout scope.

Instead, Ruger chose to use "Accurate hammer-forged, heavy barrels" . . .
http://www.ruger.com/Firearms/FAProdView?model=17915&return=Y

. . . and then affix a 6.625-inch "scout rifle" barrel-mounted rib.

http://www.shootingtimes.com/longgun_reviews/STscout_102606D.jpg



That rib is a separate piece, attached with four screws and two pillars:

http://www.ruger.com/Firearms/images/ExplodedViews/22-1.gif

Why did Ruger go to all that seemingly extra trouble?

Boston

[H2O MAN]

Ron Smith likes the Chinese M14S forged receivers, but they are too soft and need to be re-heat-treated (a service he offers).

Yes, Ron really likes the Chinese M14 receivers - they are 2nd best behind his own SEI receivers.
I'm told LRB will soon tie for 2nd best if they keep making the changes Ron has suggested.


A small number of the receivers were soft and needed to be re-heat-treated, but most do not need this service.
To date, Ron has built for me four rifles on Chinese receivers - he checked all 4 for hardness and did not have to heat treat them.
My policy with Ron is "if it needs it - do it" and the results have been outstanding :D

[JesseL]

Why did Ruger go to all that seemingly extra trouble?

Just a guess here:

Because they're already set up to make hammer forged barrels, and it's ultimately cheaper to drill & tap their existing barrel and affix a short rib, than it would be to add a parallel manufacturing process just for casting and machining barrels with integral ribs. It's really much less trouble.

It's all about making the most of the equipment and processes they already have. I don't think that Ruger's Newport NH facility; where their rifles are made; is set up to do button or cut rifling of rifle barrels. The barrels made in Prescott for Ruger's centerfire pistols are cast as one piece with integrated locking and camming surfaces, and then have their rifling cut.

[JohnKSa]

I believe they already have the ribs as well. Isn't it pretty much identical to a part on one of the No. 1 models?

[daniel (australia)]

Yep, if you're already tooled up to produce barrels for your whole range of rifles by rotary hammer forging, which involves vast capital cost but very low per-unit cost, and you have tooled up to make the little quarter rib for another line via investment casting, why would you set up a completely separate and new process for a niche model? It makes far more sense to mix and match from the existing parts bin.

Besides which, the rotary forging used for barrel-making, like investment casting, is pretty much a net-shape or near net-shape process anyway - you can produce the exterior profile, rifling and even chamber all in one process, and it is hugely efficient. I very much doubt you could produce barrels much more efficiently or economically. You produce a little quarter rib, for which you already have the tooling, for a few cents a unit, screw it onto an otherwise standard product and voila, a new model for the marketing department . Production engineering at about its simplest.

Actions of course are a whole different ball game: it is a long way from the forging to the finished product - a forged action requires complex multi-axis machining, and a fairly substantial amount of it. That costs.

[Boston T. Party]

from daniel:
Besides which, the rotary forging used for barrel-making, like investment casting, is pretty much a net-shape or near net-shape process anyway - you can produce the exterior profile, rifling and even chamber all in one process, and it is hugely efficient. I very much doubt you could produce barrels much more efficiently or economically.
Good point, thanks.

However, I remain very skeptical that a cast-steel rifle barrel (of
forged-steel thinness/weight) would be suitable for 50,000+ c.u.p.
rifle cartridges.

Boston

[harrydog]

I know it's apples to oranges, but in high performance automotive applications where high RPM and high stresses will be encountered, forged or billet steel crankshafts and connecting rods are always used as opposed to cast cranks and rods.

[Ash]

This racing car angle is interesting, particularly since racing engines don't last very long. Granted, they are subjected to tremendous stresses, but these great and wonderful forged parts are never expected to endure long-term. They are wonderfully strong and capable for short-term use, but they are worn out very quickly. Of course, a cast part might just wear sooner, but their application is completely different than, say, my Cherokee which has 230,000 miles - hard miles - on it.

Naturally, I cannot comment on whether or not a forged part would be holding up well at this mileage standard, but to compare the parts in race cars tends to point towards parts to be used very hard but not very long. That is doubtlessly not the goal of those posters defending forgings, but do I want a race gun to last 1000 rounds or do I want a rifle to last 200,000 rounds? By the way, FN not only changed the Hi-Power to cast, but also the FAL. Nobody says the forged Imbel FAL is better than the cast FN FAL.

Ash

[SlamFire1]

This racing car angle is interesting, particularly since racing engines don't last very long


The engine has to last one race, then it is completely rebuilt. I was told by a guy in the business, that if you expect to race, the minimum amount of cash you need is $30 million per year. And that was a couple of years ago, this might be up to $50 million now.

Priorities are entirely different when cost is not an issue and winning is the only measure of success and guarantee of future financial solvency.

[Ash]

That's my point. Racing tires don't last an entire race and the engine lasts one race. You can say that forged parts are used in racing engines, but I can dismiss such engines as pieces of crap because they don't last more than 500 miles. Heck, a Trabant engine lasted longer than that! Heck, why not buy Quaker State oil since they are used in so many race cars!

The point is, the argument is not really suitable as such engines don't last long. The flip side, of course, is that they are very high performance when they are being used and as a part of that, some components are not scrapped after every race. All the same, the comparison is very easy to dismiss.

Ash

[Boston T. Party]

Given the cost of replacing/rebuilding race-car engines
after every race, you'd think the cost savings of cast
parts would be alluring.

Forged parts are more expensive. There's a reason why
teams pay for them.

By the way, FN not only changed the Hi-Power to cast, but also the FAL. Nobody says the forged Imbel FAL is better than the cast FN FAL.
Oh, I'd bet that somebody will in time.
Maybe me!

Boston

[Stinkyshoe]

FYI, some Kimber 1911 Barrels are also cast. That's kinda scary, considering they are supposed to be some of the best 1911's. Funny how advertising works...:uhoh:

[harrydog]

It's not only racing engines that use forged cranks. Most high performance road cars do and in fact many regular road cars use them. Honda, VW, Audi, Subaru, Porsche are some that immediately come to mind and some of these cars last 200K or 300K miles. So forged parts don't wear out any more quickly than cast parts.
Racing teams use forged parts because cast parts probably wouldn't even last through one race.

[Shear_stress]

FYI, some Kimber 1911 Barrels are also cast.

Not sure where you picked that one up. Their barrels are forged, just like their slide sand frames.

[SlamFire1]

It's not only racing engines that use forged cranks. Most high performance road cars do and in fact many regular road cars use them. Honda, VW, Audi, Subaru, Porsche are some that immediately come to mind and some of these cars last 200K or 300K miles. So forged parts don't wear out any more quickly than cast parts.
Racing teams use forged parts because cast parts probably wouldn't even last through one race.

I know for a fact that big diesel engines use cast iron cranks. I had two tours of a Caterpillar engine plant. Both times I saw big cast iron crank casting being machined and installed in the largest darn engine blocks around. We are talking about 1500 HP engines being considered small engines in that plant. Monster engines, things with 20 cylinders. A cost of a $70 K Porsche would not equal the price of two months fuel bill.

The first overhaul is about 12,000 -15,000 hours. And that is basically seals liners, rings. Definitely not time for a crank change. Lifetime of a 200,000 mile car, about 3,333 hours at 60 mph.

Casting work fine in the proper application.

[Ash]

Boston,

It remains that race cars don't have long service times. And longevity is the point. Arguing that a forged part in a race car equals longevity is no argument at all. Said forged part lasts a short time and is replaced. This is not an argument either pro or against either form of manufacturing, only that the race car comparison is not valid.

And, still, nobody claims that FN-FAL's are inferior.

Ash

[Stinkyshoe]

Shear_Stress

This I heard from a very credible member of the American Pistol Smiths Guild. I assume he'd know.

Ss

[harrydog]

Ash,
I think you're the one who brought up the longevity issue in that forged parts wore out more quickly based on what happens in a race car engine. I was merely pointing that forged cranks are also used in many production road cars where longevity is important.
My original point was that forged parts, cranks and connecting rods in particular, are generally stronger than their cast counterparts and that is why they are used. In many racing applications a cast crank would end up cracking under the high stress.
The only real advantage of cast parts over forged or machined from bar stock parts is the manufacturing cost.

Slamfire,
Some of those big diesel engines may have cast cranks but they are very low RPM engines.
It's high RPM that really stresses a crankshaft. But even so, I did a search and it appears that many diesel engines including Cummins and Caterpillar are using forged steel cranks.

[SlamFire1]

Slamfire,
Some of those big diesel engines may have cast cranks but they are very low RPM engines.
It's high RPM that really stresses a crankshaft. But even so, I did a search and it appears that many diesel engines including Cummins and Caterpillar are using forged steel cranks

I can believe that. I would love to have seen a forging press large enough to stamp out some of the cast iron cranks I saw. They were huge. And those engines, they are designed to run 1500 rpm for forever. Not to say the loads don't vary, but they are not high rpm.

If you want to see the world's largest diesel, take a look at the pictures on this site.

http://people.bath.ac.uk/ccsshb/12cyl/

[harrydog]

Holy crap! Now that's a huge engine. At 1660 gallons of fuel per hour, imagine how much fuel it has to carry to cross the Pacific or Atlantic!

[Ash]

"I think you're the one who brought up the longevity issue in that forged parts wore out more quickly based on what happens in a race car engine."

No, I actually did not. My point merely was that using a race car is not a good example of longevity or superiority of forged parts. Indeed, I said “They (race car parts) are wonderfully strong and capable for short-term use, but they are worn out very quickly. Of course, a cast part might just wear sooner."

The point is, race cars are bad examples for any kind of longevity comparisons, whether they be tires, engine oil, or metals.

Ash

[daniel (australia)]

In relation to crankshafts and rods I said this back at post #58 in this thread

If we compare a forged steel crankshaft or con-rod with one of conventional spheroidal graphite or nodular cast iron the forged steel will generally be significantly better, at least for racing and high duty. That is not because of strength though but resistance to fatigue failure, which is admittedly much better for forged steel than any cast iron or even the general run of cast steel.

Fatigue is a big factor for cranks and rods, but not rifle receivers: a crank and rods will undergo more load cycles in a few seconds at full noise than a rifle receiver will undergo in its entire service life. That is why as well as specifying a forged crank your tuner will also be obsessive about radiusing all corners, shot peening and polishing, crack testing, and balancing, all to reduce the likelihood of fatigue cracks being initiated. None of this is relevant to rifle receivers.

There are better materials than these for racing car components too, such as Metal Matrix Composites, already seen and then banned from use in F1 pistons. MMCs are generally produced by casting or else powder metallurgy, and have particular advantages for pistons due amongst other things to the thermal loads.

F1 engines do use investment castings in the form of valves, valve-train components, blocks, gearbox housings and a myriad of others. The rules specify a steel crank though, so that is what is used.

Generally cranks and rods aren't running at stresses anywhere near their maximum strength, unless something goes seriously wrong. Nor do they wear much, even in race engines, unless bearings and/or lubrication are inadequate. The main thing that will bring their service life to an end, often in the form of an expensive unplanned reorganisation of the engine design, is fatigue. Fatigue is where a crack gets a start, perhaps in a sharp corner or defect, and under the enormous number of load cycles these components undergo it gradually progresses acoss the section, until there's not enough left to support the load and the whole thing lets go in a cloud of oily smoke and swearing.

Now fatigue life depends on a number of factors, including the material chosen, how well it is radiused, peened etc to minimise or eliminate possible crack initiation sites, and the applied stress. Now of course a race engine crank runs at fairly high stress, especially as it will generally be specced to be fairly light, but you can also reduce the stresses by good balancing and a few other tricks. Frequent tearing down and inspection including crack testing also helps you to keep an eye on things, and (ideally) swap out components before fatigue cracks can do damage.

In the case of the big diesel it has a massive crank running comparatively slowly, so fatigue is much less a factor. It probably also has pretty massive conrods too, and fairly low piston velocity, as well as running at a fairly constant speed without sudden accelerations. The net effect is that the big diesel can well get away with a nodular iron crank (one of a size which would be exceptionally difficult to produce by forging too), and very long maintenance intervals/service life.

In the case of the race car, even if the rules didn't specify it, the steel crank would be better than the iron largely because the steel is better able to resist fatigue. There are potentially even better materials too, though for F1 at least steel is mandatory.

Point is though, that all of this is entirely irrelevant to the use of investment cast components in firearms. No one is talking about making a receiver from nodular or SG iron, just for starters. More importantly though fatigue resistance is just not a factor in the case of sporting firearms. As I said a couple of weeks ago

a crank and rods will undergo more load cycles in a few seconds at full noise than a rifle receiver will undergo in its entire service life.

In any design, you have to look at the properties the material needs to have for that application, not how well suited it is to some other, entirely different application.

[harrydog]

Caspian sells excellent cast steel 1911 receivers. They have proven to be every bit as durable as forged or bar stock receivers and carry a lifetime warranty against cracking. However, for their slides they use forged steel because a cast slide would not last nearly as long. Slides endure greater stress and impact than receivers.
Cast parts may be perfectly fine for many applications but they are almost always specified only because they cost less to manufacture, not because they are better.

[Boston T. Party]

Cast parts may be perfectly fine for many applications but they are almost always specified only because they cost less to manufacture, not because they are better.

That seems an excellent and accurate encapsulation of the issue, thanks.

Regarding McClung's contribution to my book Safari Dreams, it was
in context of cast steel receivers in dangerous game rifles. For such
a gun, you want every possible odd in your favor, such as controlled-feed,
M98 extractor, fixed ejector, ample caliber, etc. I still agree with McClung
that a forged-steel receiver adds to your odds, and that a cast steel
receiver does not (and possibly lowers your odds).

If you don't have to take an unnecessary chance, why do it when a
forged Win M70 or CZ550 Magnum is available for the same price?

Regarding daniel's contention that 4140 steel has a sufficiently low
carbon content to avoid the dendrite paths from the casting process,
I'm sure McClung will respond to that when he has a moment.

Thanks to all so far for your comments.
I'm always up for learning something, or correcting my own misinformation.

btw, my book Safari Dreams is in, and turned out very nicely.
If you're keen to hunt in Africa, it will be a great use to you.

$36 cash gets you a signed postpaid copy.
352 pages, 100 color photos

Javelin Press
POB 31
Ignacio, Co. 81137-0031

Regards,
Boston

[Boston T. Party]

Quoted below in full is McClung's email.

Boston


Boston,
My response, and then I am done with this:

One has only to view the scrap piles of visibly flawed and
mis-cast pieces behind Ruger's casting plant, which is proximal to
my own place of business, or interview several hundred current and
former Ruger employees who will candidly discuss the goings on
there in terms unseen in Ruger's promo videos... to get the idea
that their manufacturing, casting and QA process subsets do not
necessarily guarantee top quality results.

Watching them begin the re-grind/re-melt recycling process of all
of this scrap, tons of it, (not always perfectly sorted for alloy content
but then, dilution does wonders for that...right?), is entertaining in the extreme.

In response to the smugly pedantic "Daniel", the cooling rate must be
optimized to prevent the formation of dendrites and other cooling
related issues. It is apparent after examining many samples of Ruger
castings that their cooling process is not what we would call "consistently
optimized". But again, Ruger's sentiment on casting quality seems to be
that what you can't hit consistently through precision and repeatability,
you can hit haphazardly often enough to make it worthwhile to keep on
plugging away at it. Fortunately for them, casting is a cheap foundry
process and "do overs" are easy.

But for Daniel or anyone else who may be emotionally invested in their
investment cast guns or have a personal interest in promoting/selling them:
If you like that stuff, fine. Buy it, sell it, whatever.
It's your money, your life on the line and as always, YMMV. ;)

Mine doesn't. It's a science thing.

Stay Sharp,
Mad Dog

[JohnKSa]

the smugly pedantic "Daniel", Cheap shot.

Posting an email from someone else that insults a member on THR when you can't do it yourself per the forum rules.But again, Ruger's sentiment on casting quality seems to be that what you can't hit consistently through precision and repeatability, you can hit haphazardly often enough to make it worthwhile to keep on plugging away at it.This is why Rugers are known for breaking... :rolleyes:But for Daniel or anyone else who may be emotionally invested in their investment cast guns or have a personal interest in promoting/selling them:Naturally, anyone who disagrees with the esteemed Mr. McClung must be doing so out of emotion or personal interest. Apparently he finds it unfathomable that there could be a disgreement based on any thing technical. :rolleyes:

[SlamFire1]

One has only to view the scrap piles of visibly flawed and
mis-cast pieces behind Ruger's casting plant, which is proximal to
my own place of business, or interview several hundred current and
former Ruger employees who will candidly discuss the goings on
there in terms unseen in Ruger's promo videos... to get the idea
that their manufacturing, casting and QA process subsets do not
necessarily guarantee top quality results.


Scandal mongering employees seldom have nice words to say about their employer. In fact, with a little prompting you can get from any employee of any business a long litany of why things are messed up at work.

And the fact there is a pile of rejects means a least there is a QA process, maybe not to the satisfaction of disgruntled former employees.

As to the complaints; yes, overall the earth is messed up and the country is going down a rat hole, but what specifically are the incidents that they are complaining about? Dollar coffee machines?, not enough parking spaces at work?, etc? I have heard any number of employees dog the products that their employer makes, and yet I have never heard any employee admit that they personally, with malice and forethought, sent out product that was dangerous or defective.

Disgrunted employees find out later they had it good when their jobs are off shored.

[harrydog]

This thread has taken a turn for the worse which I don't really want to get caught up in, but I do have a question regarding Ruger castings.
My question is, are Rugers really known for breaking? I thought it was just the opposite. I know that Caspian has never had a 1911 receiver returned to them due to cracking or breaking, and they are cast by Ruger. Also Ruger revolvers and rifles are known for being extremely strong and durable. More so than some of their competition. So I'm wondering where the "known for breaking" comes from.
By the way, I don't own or never have owned a Ruger, so I really don't have a vested interest in this at all.

[daniel (australia)]

My response, and then I am done with this...

Well, yeah, whatever…:rolleyes:

I have to laugh though, especially at this bit:

for Daniel or anyone else who may be emotionally invested in their
investment cast guns or have a personal interest in promoting/selling them

I have no financial or personal stake in this argument at all. Sure, I did write an Honours thesis on the production of high integrity castings, and I did spend a bit of time in researching, testing and developing this sort of stuff for defence and other applications, but that was a fair while ago. I spent rather more time as a metallurgical consultant, mainly investigating failures, and I’ve seen them in all sorts of products, so I don’t think I’m “emotionally invested” in any particular production method either. I’ve moved on even from there though, and my interest in all of this is in the “science thing”, and nothing else.

I note with some amusement though that Mr McClung in fact does have a financial stake in forged receivers, given that they are sold by his company – as of course does the fellow who chose him to provide “technical” input to a book he keeps mentioning.

The “science thing” too, I had to smile a wry smile at that. :p

For starters:

the cooling rate must be optimized to prevent the formation of dendrites and other cooling related issues.

McClung claimed earlier that you’d get dendrites of carbide, so assume that is what he is talking about here.

The credibility gap is yawning wider though: with the steels we’re talking about it doesn’t actually happen that way at all. This is all fairly basic metallurgy, and there are vast atlases of diagrams based on enormous amounts of empirical data showing precisely what does happen with different alloys as they solidify slowly (phase equilibrium diagrams) and as they are cooled at varying rates from slow furnace cooling to rapid quenching (TTT diagrams). With a medium carbon (“hypoeutectoid”) steel such as you might use for a receiver, cooled slowly from liquid, the steel doesn’t solidify all at once, but in fact the first thing to solidify is the ferrite, not the carbide. Ferrite is essentially pure iron (with a very small amount of dissolved carbon). Carbon is concentrated in the remaining liquid until it reaches about 0.8%, and this solidifies as a phase called pearlite, consisting of laminations of carbide and ferrite. You’ll see the resulting microstructure in cast steel and you’ll also see it in annealed forged steel of the same composition.

What about dendrites though? Well, by and large metals solidify by forming dendrites. Steel is one of them. Dendrites are no more than the name for what you see in the development of the crystal structure from the liquid as the metal cools, as a sort of branching framework which grows until the whole structure is solidified
http://www.rpi.edu/locker/56/000756/jpegs/dendmicr.jpg
You see the same type of crystallisation at work in snowflakes. Saying you'd prevent the formation of dendrites as you make steel is a bit like saying you can prevent a tree from containing wood. Moreeover, as I’ve said, the ferrite actually forms first in the steels we’re talking about, not the carbide, so the dendrites from which the crystals start to grow consist of this ferrite.

As for "cooling related" issues, you get these with forgings too. Quench cracking for example, or distortion, or wrong hardness. All of these are "cooling related". You avoid them with good process control, and the same applies to castings.

One has only to view the scrap piles of visibly flawed and
mis-cast pieces behind Ruger's casting plant…
…Watching them begin the re-grind/re-melt recycling process of all
of this scrap, tons of it, (not always perfectly sorted for alloy content
but then, dilution does wonders for that...right?), is entertaining in the extreme.

You’ll always have some scrap, with any casting process, mainly in the form of sprues, risers etc. You’ll get rejects too, for any number of reasons. Same with any process. It says nothing of the comparative merits of the product, and I suspect is being grossly exaggerated here.

In foundry practice you simply recycle the metal back into the furnace. As to segregation according to alloy again I’d be surprised if Ruger wasn’t doing this, as it is standard practice in any foundry I've been in, but in any case it is also standard practice to analyse each heat immediately before pouring and make any adjustments to bring it to spec. I’ve done this myself, many times (though a long time ago): it takes a matter of minutes to carry out a spectrographic analysis and calculate the alloy additions to bring an off-spec. heat to spec again, before you pour.

As for disgruntled employees well, I take such hearsay with a substantial grain of salt. It wouldn’t prove anything about the relative merits of forging and casting anyway. In any case it is no secret that there’s been a significant shake up at Ruger's factory over the past year or so. They sought to reduce inventory significantly and it exposed problems in their manufacturing systems which they've had to bite the bullet and address. That has nothing to do with the relative merits of forging and casting either.

I don’t place all that much credence in one firearm supplier running down another’s product either, but that is all I see here. Where's the "science"?





.

[SlamFire1]

I don’t place all that much credence in one firearm supplier running down another’s product either, but that is all I see here. Where's the "science"?

Daniel: Knock em dead mate:

We all know that vendors always fairly rate the products of their competitors. :rolleyes: Rubbish!

All I read from the critics of casting is unsubstantiated mud slinging. Almost at their last stand. The final stand will be that they don't like casting because they don't like the people who make castings.

These guys trust their lives daily on the cheapest cast components in one of the deadliest games around: Cars. Like 50,000 US citizens die per year and there are 600,000 vehicle injuries.!!

But what they emphasize is a cast receiver failing during a what, a maybe once in the lifetime hunt against lions and tigers and bears!

[JohnKSa]

My question is, are Rugers really known for breaking?The little "eye-rolling smiley= :rolleyes:" is indicative of sarcasm. ;)

You are correct. In spite of all the innuendo about QA issues and casting problems from our "expert", Rugers have a well-deserved reputation for extreme durability.I don’t place all that much credence in one firearm supplier running down another’s product either, but that is all I see here. Where's the "science"?Agree, the email is several paragraphs of attacks and innuendo with maybe a couple of sentences of technical information (being generous).

I'm always terribly unimpressed with people who claim to be experts but when pressed choose to resort to pomposity, innuendo, and insults rather than responding technically.

[Boston T. Party]

Cheap shot.

Posting an email from someone else that insults a member on THR when you can't do it yourself per the forum rules.I understand the point, but didn't consider "smugly pedantic"
to have crossed the line of insulting. It certainly wasn't my
intention to insult or facilitate such. From here on, I'll post
only what I have to say.


from Daniel:
I note with some amusement though that Mr McClung in fact does have a financial stake in forged receivers, given that they are sold by his company – as of course does the fellow who chose him to provide “technical” input to a book he keeps mentioning.Actually, I've no financial stake in any forged steel product.
I wrote a book containing the opinions of myself and others.
I've never found any reason to doubt Kevin's technical
expertise in my 16 years of knowing him. He exposure of the
Zylon material failure in bullet-resistant vests points to his
wide understanding of material properties.

Before I published Kevin's essay on the subject, I searched
diligently for facts and discussion on the forged vs. cast issue,
but this thread did not come up. (I found it only post-publication
when I was running down whether or not Montana rifles were
cast, and posted on it that same day.)

Kevin, to my knowledge, has nothing personal against Ruger
that would color his stance against cast steel receivers.


_____________
Regarding the veracity of Ruger's former employees, I cannot
comment to that with any knowledge, though I take the point
that some may be bitter and have an agenda.


_____________
from Daniel:
With a medium carbon (“hypoeutectoid”) steel such as you might use for a receiver, cooled slowly from liquid, the steel doesn’t solidify all at once, but in fact the first thing to solidify is the ferrite, not the carbide.
Is it your contention that cast receivers of “hypoeutectoid” steel
are slowly cooled?

If, however, they are cooled fast, does that tend to collect
carbides in a fern-like lattice vs. randomly distributing them?


_____________
In order to constrain this thread within technical bounds,
I pose the following question:

Assuming two bolt-action receivers of identical dimensions and
weight -- one constructed in forged steel and other in cast steel
(both of the best steel, process, and QC) -- would anybody here
assert that the cast version is of equal or superior tensile strength?

(Interestingly on this very point are two virtually identical rifle
receivers: the forged Win M70 Classic and Montana's cast version
of it. The Montana action may be heavier, however.)

Thank you all for your posts.
My only reason for posting is to further understanding of this issue.
May true science win.

Boston

[JesseL]

Assuming two bolt-action receivers of identical dimensions and
weight -- one constructed in forged steel and other in cast steel
(both of the best steel, process, and QC) -- would anybody here
assert that the cast version is of equal or superior tensile strength?

(Interestingly on this very point are two virtually identical rifle
receivers: the forged Win M70 Classic and Montana's cast version
of it. The Montana action may be heavier, however.)

I would assert that until they do some serious real-world testing and analysis of both receivers, nobody is qualified to state definitively which receiver is stronger. No science exists in a vacuum (except maybe pure mathematics).

[Boston T. Party]

Surely a test of two otherwise identical steel cavity forms
has been done to ascertain the strength of casting vs. forged.
If so, where?

Remember, my question is not whether a cast receiver can be
sufficiently oversized to equal the strength of a (thinner) forged
receiver, but, rather, the comparative strength of equal weight
and thickness of the two.

Boston

[hubel458]

A false premise-It should be stated how much thicker forged
reciever has to be to match investment one.

Don't do no good badmouth investment cast, heat treated stuff .
I have stressed tested the Ruger 77, and emphatically
state that they are stronger than the forged Win 70.
And the Win 70 and many others are thicker at the side of
reciever ring in same place as the flat side of the Ruger 77, where
the 77 is thinnest where if it was going to split, that's the place.
I overloaded, not by plan, a 77 in 458, so bad it bulged chamber ahead
of the reciever about ..060, flowed the brass case around bolt,
but it didn't blow out the corners of the case, or shear the lugs
or shear the lug seats. Took out barrel with lathe, tested action, put
in other barrel still going after another thousand rounds, I know that
the Win wouldn't of held. The investment casting can be treated to higher
strength than forged. Can be treated more uniformly throughout
thus giving a much higher strength all through the material.
They both have same diameter barrel thread
but the Win is about .025" bigger OD than Ruger on the sides, and
the Win wouldn't have held like the Ruger. Ed

[SlamFire1]

I would assert that until they do some serious real-world testing and analysis of both receivers, nobody is qualified to state definitively which receiver is stronger. No science exists in a vacuum (except maybe pure mathematics).

I agree. I can recall reading something in the 70's where Ruger shear tested the lugs on their bolts and found they took twice the shear of forged bolts. But, if memory was right, the forged bolts were like M1903 bolts. The material technology and process technology was decades different, so it was not an apples to apples comparison. The tests were not published in the open literature.

But I want to say, at some point the tensile and ultimate of the receiver becomes meaningless. Steel is far stronger than brass. At some pressure point the cartridge ruptures. I personally think action strength is really a measure of how well the action design supports the cartridge case. If the action properly supports the case, than a plain carbon steel action, like the M38 Japanese, will prevent cartridge rupture far better than the more massive M1917. Which was made of nickel steel. P.O Ackleys’ tests show this.

Once the cartridge ruptures, the next issue is how well the action protects the user in what is, essentially, a destructive incident.

I don’t think anyone ever designed an action with the idea that after a “catastrophic” failure, that all the user had to do was screw on a new, intact barrel. It is just good fortune that some have useable receivers after such events. If I were the designer, I would consider the safety margin of the action to have been used up. If these were not individuals, but were rather companies or Armies, I have no doubt that even though the receiver was still intact, it would have been scrapped. Individuals don’t have such deep pockets so ……..

In the book "Technical Notes" from Armalite, the load of a 30-06 on the bolt face is between 4000 and 6,600 pounds, for a couple of milliseconds. I will bet the wheel bearings on my truck experience more than that on some big pot holes.

I think the focus on cast versus forged is a distraction, created by corporate advertising, from what is the real issue: Good action design.

And for that, go read Stuart Otteson’s books on “The Bolt Action”. Good action design is far more complicated than material choice.

[hubel458]

Thr reciever besides being intact was also tested.
No weaknesses showed up. Total loads fired through it
is about 2000, half before the overload and half after.
Proper investment, alloyed and treated steel isn't going to
stress away so to speak, unless you subject it to many
tens of thousands of pressure cycles, may take hundreds
of thousands. Now it may fail in a few hundred of my stupid
overloads, but that would be awful expensive for barrels to
find out.Ed

[Boston T. Party]

from Daniel:
With a medium carbon (“hypoeutectoid”) steel such as you might use for a receiver, cooled slowly from liquid, the steel doesn’t solidify all at once, but in fact the first thing to solidify is the ferrite, not the carbide. Ferrite is essentially pure iron (with a very small amount of dissolved carbon). Carbon is concentrated in the remaining liquid until it reaches about 0.8%, and this solidifies as a phase called pearlite, consisting of laminations of carbide and ferrite.

You contend that steel alloy with <0.83% carbon does not form
carbides because up to 0.83% carbon is dissolved in the
austenite (gamma iron in liquid phase).

This is a partial truth.

Hypoeutectoid alloys contain less carbon content than the maximum
dissolvable in the parent material of austenite. (The introduction of carbon
into austenite lowers its temperature of stability, but that effect peaks
at about 0.83% carbon content.)

Such alloys with <0.83% carbon will indeed form carbides, though only with
ferrite (called cementite, or Fe3C) because the austenite first dissolves carbons
until its saturation point of 0.83%. Cementite plus ferrite -- and slowly cooled --
is what creates the phase of pearlite (+ free ferrite), beginning at 0.20% carbon.
Beyond 0.83% carbon, you get free ferrite, pearlite, and non-ferrite carbides
(i.e., with the other alloys such as vanadium, tungsten, etc.).

No gun manufacturer wants pearlitic steel because the very definition
of pearlite means that the once-dissolved-in-austenite carbons were
foolishly allowed to precipitate out of the austenite solution to form
segregated cementites (Fe3C). The whole point of a rapid cooling of
AISI 4140 gun receiver steel (which is oil quenched for 30 minutes from
an initial temp of some 1525°F/1625°F, by the way, not "slowly cooled"
as in your model) is to trap individual carbon atoms within the austenite
crystals, creating tough martensitic steel.

http://info.lu.farmingdale.edu/depts/met/met205/tttdiagram.html

(If you quench too slowly, you end up with a phase between pearlite and
martensite called bainite, but that's a matter irrelevant to our discussion.)

Yes, quench stresses can form from the formation of martensite, but that
is why such are relieved through subsequent tempering.

The fact that gun receiver steels such as AISI 4140 are <0.83%/hypoeutectoid
alloys is really immaterial regarding the issue of carbides segregating into
dendrites. By definition, steel is iron with at least 0.20% carbon, else the
iron could not be formed into martensite (i.e., hardened). And even such
a low carbon content of 0.20% will precipitate out if the austenite
were allowed to be "slowly cooled" as per your example.

I am trying to imagine further your point, to wit, that 4140 cast steel's
carbon will necessarily form into pearlite cementite layers vs. dendrites,
but that is not a given at all. Such in part must assume not only a forged
steel quality of alloy distribution, but also no internally disparate cooling
(i.e., crystallization) of the cast piece within its mold.



Moreeover, as I’ve said, the ferrite actually forms first in the steels we’re talking about, not the carbide, so the dendrites from which the crystals start to grow consist of this ferrite.Not exactly:

The area along which crystals meet, known as the grain boundary, is a region of mismatch. The boundaries are formed by materials that are not part of a lattice, such as impurities, which do not show a specific grain pattern. This leads to a noncrystalline (amorphous) structure at the grain boundary with the atoms irregularly spaced. Since the last liquid to solidify is generally along the grain boundaries, there tends to be a higher concentration of impurity atoms in that area.

http://info.lu.farmingdale.edu/depts/met/met205/crystallization.html

If carbon solidifies last, then that helps to prove my point that carbides will
tend to accumulate along the grain boundaries, especially during internally uneven
parts crystallization.


I will grant you that >0.83% carbon content austenite (hypereutectoid steel),
all other things being equal, is more prone to grain boundary carbide dendrites,
but I do not at all agree that such dendrites are impossible or even rare in
hypoeutectoid steels (especially such cast instead of forged).

Does forging more effectively distribute dissimilar alloys within the austerite?
Of course it does, that's one reason for the operation. There really can
be no disagreement about that.

Quality hot forging of carbon steel distributes the alloys, and the oil quench
"freezes" this distribution in place for optimal strength. After nearly many
hours of research into all this, I'm really astounded that the matter can
seriously be called into question at all.

Regards,
Boston

[daniel (australia)]

Looking back at my last post I should correct something I wrote – not that it changes the thrust of the argument but because I misstated something inadvertently, and it should be fixed: it is of course the generally the metastable austenite which nucleates first. Ferrite then appears as a transformation product from the austenite with decreasing temperature, and finally at about 720 degrees C the remaining austenite undergoes an isothermal transformation to pearlite.
Hypoeutectoid alloys contain less carbon content than the maximum
dissolvable in the parent material of austenite. (The introduction of carbon
into austenite lowers its temperature of stability, but that effect peaks
at about 0.83% carbon content.)

Such alloys with <0.83% carbon will indeed form carbides, though only with
ferrite (called cementite, or Fe3C) because the austenite first dissolves carbons
until its saturation point of 0.83%. Cementite plus ferrite -- and slowly cooled --
is what creates the phase of pearlite (+ free ferrite), beginning at 0.20% carbon.
Beyond 0.83% carbon, you get free ferrite, pearlite, and non-ferrite carbides
(i.e., with the other alloys such as vanadium, tungsten, etc.).
Well, yeah, but in the hypoeutectoid alloy, cooled slowly enough to avoid transformation to martensite or bainite, the carbide is all in the form of pearlite, which is a fine laminated structure – fine layers of hard carbide and soft ferrite combining to make a comparatively strong and tough structure.
No gun manufacturer wants pearlitic steel because the very definition
of pearlite means that the once-dissolved-in-austenite carbons were
foolishly allowed to precipitate out of the austenite solution to form
segregated cementites (Fe3C).

No, no, no! In the annealed or normalised condition you are going to have the same percentages of pearlite and ferrite for any given composition, regardless of whether the steel was forged, machined from bar stock or produced as a casting. You then heat treat. Further, the carbide in these grades isn’t precipitated out of the austenite, nor does it form segregated cementites. Instead the remaining austenite transforms isothermally to the new structure, pearlite.
The whole point of a rapid cooling of
AISI 4140 gun receiver steel (which is oil quenched for 30 minutes from
an initial temp of some 1525°F/1625°F, by the way, not "slowly cooled"
as in your model) is to trap individual carbon atoms within the austenite
crystals, creating tough martensitic steel.
You are confusing a couple of important points here. First, investment castings are, in my experience, poured into investments (moulds) which have been preheated in a furnace to about 1000 degrees Celsius or so, and allowed to cool over a period of hours. It is not equilibrium cooling but nor is it anywhere near being quenching. You then clean off the mould material, do any finish machining and of course you are then at liberty to heat treat them any way you like. The same is true of forgings: you forge at temperatures above the austenite transformation temperature, cool slowly, and generally do your machining in the same normalised state, before heat treating to develop the final hardness. The reason is fairly simple: it is easier to do any machining before hardening. In either case though whenever you are ready you can quench and temper the product, or use some other heat treatment, to get the final properties you want.

The fact that gun receiver steels such as AISI 4140 are <0.83%/hypoeutectoid
alloys is really immaterial regarding the issue of carbides segregating into
dendrites.
Except to the extent that, in direct contradiction of your earlier claims, carbides just don’t “segregate into dendrites” in these alloys.
Quote:
The area along which crystals meet, known as the grain boundary, is a region of mismatch. The boundaries are formed by materials that are not part of a lattice, such as impurities, which do not show a specific grain pattern. This leads to a noncrystalline (amorphous) structure at the grain boundary with the atoms irregularly spaced. Since the last liquid to solidify is generally along the grain boundaries, there tends to be a higher concentration of impurity atoms in that area.http://info.lu.farmingdale.edu/depts...llization.html
If carbon solidifies last, then that helps to prove my point that carbides will
tend to accumulate along the grain boundaries, especially during internally uneven
parts crystallization.

The carbide appears as the result of an isothermal transformation in the solid state. It is a different mechanism from that which causes impurities to tend to concentrate at grain boundaries. In fact the carbide is exceptionally finely distributed within islands of pearlite, not at grain boundaries. As you approach 0.8%C the pearlite % increases to 100%.

Here’s a 0.3%C steel, normalised: the ferrite grains are white, the pearlite darker – you can see the laminated structure:

http://pwatlas.mt.umist.ac.uk/internetmicroscope//lib/micrographs/cmfs4-d-50um.jpg

At 0.4%, again normalised, you can see theres rather more pearlite, and less ferrite:

http://pwatlas.mt.umist.ac.uk/internetmicroscope//lib/micrographs/cmfs5-d-50um.jpg

And at 0.8% C, its pretty much all pearlite:

http://pwatlas.mt.umist.ac.uk/internetmicroscope//lib/micrographs/cmfs9-d-50um.jpg





Does forging more effectively distribute dissimilar alloys within the austerite?
Of course it does, that's one reason for the operation. There really can
be no disagreement about that.

More effectively than what? The austenite is a solution, not dissimilar alloys, and the metal is effectively mixed in the case of modern castings by a number of factors, including the churning which takes place in an induction furnace,gating and pouring processes etc. Any minor degree of segregation is easily attended to by heat treating anyway. There’s also processes like ultrasonic vibration to nucleate a fine structure, as well as various alloy additions to nucleate grains, pin growth, modify or remove inclusions etc– quite a bit is going on in fact.

Quality hot forging of carbon steel distributes the alloys, and the oil quench"freezes" this distribution in place for optimal strength. After nearly many
hours of research into all this, I'm really astounded that the matter can
seriously be called into question at all

Well I suppose that is one way of putting it. It just isn’t a very accurate way of putting it.

Let us not lose sight of the point though, that there are other processes besides forging which can give rise to a product equally suitable in terms of strength and other properties. Modern investment casting is one such process, and as I have previously said there is no technical reason why an investment cast receiver, all else (in terms of heat treatment, QA etc) being equal should be any less serviceable and safe than a forged one.

I do hope that the research you’ve done has sparked a bit of an interest, even though it is a bit late for your book

[Boston T. Party]

Thanks, Daniel, for your reply.

I do hope that the research you’ve done has sparked a bit of an interest, even though it is a bit late for your book
Since McClung's thesis in my book (and thus its discouragement
of cast steel receivers) points to the side of caution, even if such
is ever proven technically to have been in error, my readers will not have
been deprived of any safety or value because of that error.


___________
Are you contending that gun parts/receivers are generally made of
softer pearlitic steel (subsequently heat treated) vs. martensitic steel?

Further, are you contending that heat treating transforms pearlite into martensite?

I will respond to the rest of your reply when I can, but meanwhile reiterate
to you my previously unanswered question:

Assuming two bolt-action receivers of identical dimensions and
weight -- one constructed in forged steel and other in cast steel
(both of the best steel, process, and QC) -- would anybody here
assert that the cast version is of equal or superior tensile strength?

To me, this is the real question.

Neither I nor McClung disallow that a sufficiently heavier cast
receiver can have a similar working strength as a lighter forged one -- just
that such is 1) heavier, and 2) less robust over time. Your disagreement
with 2) is certainly noted, but are you also disagreeing with 1)?

Regards,
Boston

[hubel458]

Properly investment cast, heat treated, alloy recievers
and bolts are as strong as a forged ones, of the
same dimensions. Winchesters are a little thicker on
the side compared to Ruger and not even a Winchester nut
would say it would hold as much as a Ruger. Ed

[jad0110]

Next time an anti says we are just a bunch of gun loving, stupid, ignorant hicks, I'm whipping this thread out!

A great read everyone, I've really enjoyed it.

[SlamFire1]

Assuming two bolt-action receivers of identical dimensions and
weight -- one constructed in forged steel and other in cast steel
(both of the best steel, process, and QC) -- would anybody here
assert that the cast version is of equal or superior tensile strength?

The metallurgical discussion is way beyond my education, but the question of which one is stronger, seems to me to be a cart before the horse question.

How often does someone design something based only on the material considerations? I am certain you could design an action, setting as your primary design criteria, “optimization of forging properties”, but why do that? I would think other goals are more important: cost, weight, function, safety, vendor supply, tooling, production processes, just do the system engineering. What do you think are the five most important characteristics of a rifle action,? And what are you willing to pay to get that?

If your number one goal is lightweight, then the solution can be radically different then if your number goal is safety. And if safety is not an issue, only cost, you can build a cheap gun out of PVC tubing, a rubber band loaded nail, and duct tape. It will be a one shot device though!

The material choice and fabrication technique support the overall design, they are not the design, or the program will surely fail. If you have ever sat down and wrote a system requirements document, and then done the trades, you know you have to trade things off to get an acceptable design. Yes, material choices influence the design, fabrication influences the design, but so does human factors, reliablity, maintainabilty, interchangablity, size, weight, etc, etc, etc. But there is one thing that totally dominates all commerical designs, and that is cost.

On the commercial market, you have to be price competitive or the market walks to the cheaper product. And of course you cannot ignore features. The automotive industry found that people will buy one $40,000 vehicle over another, just because of cup holders.

I want to thank everyone for keeping the discussion civil and very interesting.

[daniel (australia)]

Are you contending that gun parts/receivers are generally made of
softer pearlitic steel (subsequently heat treated) vs. martensitic steel?
You ask me that as if you think they are different things…:scrutiny:

Further, are you contending that heat treating transforms pearlite into martensite?

Well, yeah, of course. What did you think?

You see, if you take a piece of your medium carbon steel and cool it slowly from a high temperature (ie from the austenite phase) you’ll end up with a microstructure composed of pearlite and ferrite, depending on carbon content, as I said in my last post. It doesn’t matter whether the steel was forged or cast. In this condition it is said to be annealed (if furnace cooled) or normalised (if air cooled) and it is comparatively fairly soft but ductile, stress free, and reasonably easy to machine.

Now whenever you want to - once you’re done machining it perhaps - you heat treat it by raising its temperature high enough to transform it all back to austenite, and then you quench, which is to say cool it so fast that ferrite and pearlite don’t have time to form again but instead you end up with a transformation to martensite, which is an extremely hard but brittle metastable phase at room temperature.

Your steel is not much use in that condition though, as it is too brittle, so you temper, by raising the temperature again to an intermediate level (below the austenite transformation temperature) to allow a certain amount of decay of the martensite structure and thereby regain some degree of toughness, though at the expense of some loss of hardness – the degree of tempering depends on the balance of these properties you want in the finished article.

BTW the process is reversible too: you can take your quenched and tempered article and heat it then slowly cool to end up back at pearlite + ferrite again, and vice versa.

I will respond to the rest of your reply when I can, but meanwhile reiterate
to you my previously unanswered question:
Quote:
Assuming two bolt-action receivers of identical dimensions andweight -- one constructed in forged steel and other in cast steel(both of the best steel, process, and QC) -- would anybody hereassert that the cast version is of equal or superior tensile strength?
To me, this is the real question.

Neither I nor McClung disallow that a sufficiently heavier cast
receiver can have a similar working strength as a lighter forged one -- just
that such is 1) heavier, and 2) less robust over time. Your disagreement
with 2) is certainly noted, but are you also disagreeing with 1)?

I thought I had answered it, but perhaps not directly enough.

I had already given the example of the aircraft parts, which have in recent times reached the stage of being no longer subject to the “casting factor” of the past.

In terms of rifle receivers though, relying on my old first edition of De Haas' Bolt Action Rifles I can give you this comparison: The weight of the Winchester Model 70 action is listed as 48 oz (45 oz in the Featherweight), the Mauser 98 as 45, Sako L61 44 oz, Brno ZKK600 43 oz and the Ruger 77 long action as 42 oz. (Perhaps someone with a more recent edition or other data could chime in with figures for some more recent designs)

All of these actions are about the same size, and for the same sizes of cartridge. I would suggest that all have proved quite sufficiently strong and serviceable, and they’re all much the same weight (though the Ruger, with the investment cast receiver, bolt, and other parts, is in fact the lightest by a small margin :neener:) In practical terms then the answer to your question must be yes.

It is however a bit of an oversimplification, and I think Slamfire makes a very good series of points. Bottom line though is that investment casting as a technique is well established as a process capable of producing an action just as strong, safe and serviceable as forging or milling from tube or bar stock.

[JohnBT]

Knowing next to nothing on the subject, I learned a lot from Bill Caldwell's posts in this 2002 thread. You can google his name for info on his custom knives and guns. John

"Forged Frame, Cast Frame : View from the Hills"

www.pistolsmith.com/viewtopic.php?t=7912

Excerpt from one of his posts in his thread:

"The so called forged frames should be called drop forged frames. Proper forging technique calls for heating the steel to a certain temperature, then hammering in a proper sequence and with varying strength hammer blows, until the steel cools to a temperature where hammering should be stopped. Then the steel is reheated and hammered again. This is repeated until desired shape and dimensions are reached. A skilled blacksmith can refine the grain structure and grain direction. No frames are forged this way. Frame forging is done by heating a chunk of steel, placing it in a die, a matching die is slammed into this, and this is the 1911 forged frame. A quick way to get the general shape of the frame. This doesn't do anything to help the steel, and unless stress relieved and annealed, the frame is loaded with stress. It will certainly move during machining and heat treating. If the steel was not at the proper temperature when the hammer falls, lots can happen. All bad. Too hot: giant and very weak and brittle grain structure. To cold: inclusions, cold shuts. Not a good foundation to build on. "

[Boston T. Party]

Yes, heating pearlite into austenite first, of course.
I thought you meant skipping the austenite phase,
and going from pearlite directly to martensite.

____________
Regarding the weight issue, I found this:

Cast-Steel

We won’t waste much time discussing cast-steel rods because they’re poorly suited to any type of serious performance use. Though the casting process is very inexpensive and results in “near net” shapes that require minimal machining, the lack of a cohesive grain pattern and compromised molecular binding yields brittle parts. Trust us, brittle connecting rods are the last thing you want in a performance engine.

In the ’60s and ’70s, American Motors, Cadillac, Buick, and Pontiac all used cast rods in a wide variety of engine designs. In an effort to improve molecular binding and strength, the molten metal was injected into the mold cavity under high pressure. The resulting castings may have been good enough for use in everything from GTOs to Jeeps, but they have no place in anything other than the most fanatical numbers-matching restoration effort. Worst of all, these cast parts had to be made heavier than comparable forged rods to maintain strength. When you consider that a cast “Arma-Steel” Pontiac 455 rod weighs 31.7 ounces and a stock Chevy 454 forged rod weighs 27.4 ounces, you’ll agree they’re the automotive equivalent of recycled cardboard.

http://www.hotrod.com/techarticles/choosing_the_right_connecting_rods/index.html

More later,
Regards,
Boston

[hubel458]

Boston- You're not comparing the same things. Those cast
rods used in those different small and big block engines
were not investment cast and properly heat treated like gun
actions and other stuff is built nowadays. And we've busted all
kinds from mickey mouse engines up to Packard PT boat engines.

Above quote-the Winchester Model 70 action is listed as 48 oz (45 oz in the Featherweight), the Mauser 98 as 45, Sako L61 44 oz, Brno ZKK600 43 oz and the Ruger 77 long action as 42 oz.

And the Ruger is strongest......Ed

[Boston T. Party]

Regarding the "Ruger 77 long action as 42 oz", that is likely the MkI
given the 1st edition of Haas's book. What do the MkII actions weigh?
I'm away from my library, so I cannot now check this.


OK, Daniel, these near-net shape investment cast parts are:

1) slowly cooled down to annealed (or normalized) pearlite/ferrite, then
2) machined (if necessary) to net shape, then
3) reheated back up to austenite transformation temp, then
4) quenched into martensite, then
5) tempered

I follow that perfectly. I think we all do by now.

However, assuming, arguendo, that when the molds were poured
the carbons were (somehow) very nicely distributed in austenite
solution, that carbon content later segregates in stage #1
(as laminar cementite Fe3C strips in pearlite/ferrite).

When that pearlite/ferrite is reheated into austenite, any previous
quality carbon distribution (i.e., in the first austenite phase
during the investment casting) is lost as this second austenite
phase is derived from pearlite/ferrite (with its carbide segregated
in cementite strips).

And how are those carbides randomly distributed in the (second)
austenite then?

The second austenite solution has none of the benefits that the
first austenite solution enjoyed, such as (you mentioned) of induction
furnace churning, gating, pouring, or ultrasonic vibration. Near-net
shape pearlite parts are simply reheated to austenite and then quenched
into martensite. (Rather, it's re-melted but not re-stirred.)

If you counter that such processes (induction furnace churning,
gating, pouring, or ultrasonic vibration, etc.) are not necessary for
a well-mixed second austenite solution, then why were such
even done at all the first time during the original casting?

I.e., if simply reheating pearlite into austenite #2 effectively "stirs" the
solution, then why bother (very elaborately) stirring it in austenite #1?

McClung's point has been that attempts to drive pearlite segregated
carbides into austenite solution are notably unsuccessful. Hence,
investment casting relying on austenite-->pearlite-->austenite-->martensite
process will have, according to his thesis, segregated carbides in the
grain boundaries. In short, mere heat treat of pearlite does not create
a well-mixed austenite (#2) and thus you can't avoid carbide strings in
your martensite.

If you have specific countering evidence on this very issue, please post
it because we've arrived (finally) at the very crux of the dispute.

___________
hubel458, are you saying that those cast con-rods were sand
vs. investment cast?


. . . I know that the Win wouldn't of held.

And the Ruger is strongest......Ed
You've been saying that anecdotally, but without any offered
empirical evidence. Just because you claim to "know" that the
Win M70 wouldn't have held up to that load your M77 withstood . . .
does not make it so.

Regards,
Boston

[hubel458]

Ruger ran shear tests of bolt lugs/bolt seats and
they were about 25% higher than what the strength of
the lugs and seats would have calculated out with tensile and
yield strengths of a forged action the same size.

As for the rods, broken ones looked just like a
maleable iron. The auto mfs I don't feel
could set up to do the bother, all the steps, and
slowdown of proper heat treatment Ed.

[Boston T. Party]

. . . would have calculated out . . .
Would have calculated out?
That's empirical evidence?
Sounds pretty thin to me.

btw, the strongest bolt-action that author Haas could find
was an Arisaka. It was almost impossible to blow up.
A forged steel action . . .

Boston

[hubel458]

I'm reporting Rugers tests, and compared with the
strength of forged based on the tensile and yield strength
of same size forged bolts and actions others built it
was stronger. Simple math, get the cross section of parts,
apply the math using the strength of metals and it gives
a result. Yes Arisaka is almost impossible to blow up,
which is great, just like a Ruger is almost imposible to blow
up. I've seen charts where properly made investment parts heat treated
right had a tensile strengths over 300,000 lbs. So all the
talk about what happens at boundary layers don't mean nothing.
Investment with treating is more uniform through out,Making for
higher strength. Ed

[daniel (australia)]

Boston

the lack of a cohesive grain pattern and compromised molecular binding yields brittle parts

How do they dream this stuff up? :rolleyes:

Leaving the truly laughable to one side though, I thought I’d dealt with the conrods, several times. You aren’t comparing apples with apples, as the method of production is different: these rods they're talking about are or were usually cast in sand moulds, though the article you posted also describes something that sounds like pressure diecasting (?), not investment casting. Incidentally I note that the article describes experiments carried out in the 1960s and 70s - which was, um, rather a long time ago;). Where the cutting edge is for high-performance conrods nowadays is squeeze cast metal matrix composites.

The other point you continue to miss (and it isn’t made very well in the article either) is that it is fatigue life not strength which is the determining performance factor in conrods. If you read the article more closely you’ll see that: as they point out your basic as-forged rod is not that great for serious high-performance either, but can be dramatically improved by surface machining, radiusing, peening and polishing, all techniques which actually make it no stronger at all, but dramatically increase fatigue life. Fatigue really isn’t anywhere near being a factor for a rifle receiver though.

Regarding the "Ruger 77 long action as 42 oz", that is likely the MkI
given the 1st edition of Haas's book. What do the MkII actions weigh?
I'm away from my library, so I cannot now check this.

I’d be prepared to bet the difference isn’t enough to help you:neener: Anyway, the comparison remains valid, as the Mk I had investment cast receiver, bolt and sundry other parts. The differences between it and the Mk II aren't really material in this debate.

OK, Daniel, these near-net shape investment cast parts are:

1) slowly cooled down to annealed (or normalized) pearlite/ferrite, then
2) machined (if necessary) to net shape, then
3) reheated back up to austenite transformation temp, then
4) quenched into martensite, then
5) tempered

I follow that perfectly. I think we all do by now.

However, assuming, arguendo, that when the molds were poured
the carbons were (somehow) very nicely distributed in austenite
solution, that carbon content later segregates in stage #1
(as laminar cementite Fe3C strips in pearlite/ferrite).

When that pearlite/ferrite is reheated into austenite, any previous
quality carbon distribution (i.e., in the first austenite phase
during the investment casting) is lost as this second austenite
phase is derived from pearlite/ferrite (with its carbide segregated
in cementite strips).

And how are those carbides randomly distributed in the (second)
austenite then?

First of all the carbide doesn’t “segregate”. It is contained within the grains of pearlite, very finely distributed. When you heat it up into the austenite range the crystal structure reorganises – in the solid state – and the carbide molecules are re-dissolved in that structure in solid solution. The molecules don’t have to diffuse far to do that, and diffuse they do, resulting in a nice uniform composition. In fact austenitising is a method also used for addressing any microsegregation of alloys in alloy steels.

When you then quench this, the speed of cooling doesn’t allow the iron and carbon to diffuse back into the ferrite + pearlite structure – that is rather the point in fact. Instead the carbon is retained in the crystal lattice as an interstitial solid solution, giving rise to a wholly different set of properties such as high hardness etc.

BTW (and not for the first time) the same mechanism is at work regardless of whether the steel was cast or forged.

The second austenite solution has none of the benefits that the
first austenite solution enjoyed, such as (you mentioned) of induction
furnace churning, gating, pouring, or ultrasonic vibration. Near-net
shape pearlite parts are simply reheated to austenite and then quenched
into martensite. (Rather, it's re-melted but not re-stirred.)

If you counter that such processes (induction furnace churning,
gating, pouring, or ultrasonic vibration, etc.) are not necessary for
a well-mixed second austenite solution, then why were such
even done at all the first time during the original casting?

I.e., if simply reheating pearlite into austenite #2 effectively "stirs" the
solution, then why bother (very elaborately) stirring it in austenite #1?

No, the “second” austenite solution is formed entirely in the solid state, by heating the steel from lower temperature, unlike the “first”, formed from nucleation and grain growth by cooling from liquid. When you are producing the casting from the liquid steel you are trying to ensure the liquid is well mixed, so as to avoid segregation or variation the composition in the casting. This is more an issue with really big castings btw, including the cast billets and slabs from which you get bar stock for forgings;).

Now if you’ve done it properly though your comparatively small receiver casting will solidify as a nice uniform austenite and, with decreasing temperature, this will transform to ferrite and pearlite. In the case of this transformation the diffusion distances the carbon travels are pretty small though, and when you heat it up again the carbon just has to diffuse back these same small distances to dissolve into a new and at least equally uniform (if not even more uniform) austenite.

McClung's point has been that attempts to drive pearlite segregated
carbides into austenite solution are notably unsuccessful. which in the context of the alloys we're talking about is utter nonsense.

Hence,
investment casting relying on austenite-->pearlite-->austenite-->martensite
process will have, according to his thesis, segregated carbides in the
grain boundaries. In short, mere heat treat of pearlite does not create
a well-mixed austenite (#2) and thus you can't avoid carbide strings in
your martensite.

Again, utter nonsense. For starters the carbide doesn’t form on grain boundaries in these hypoeutectoid steels but as lamellae in the pearlite structure in grains of pearlite. I’ve posted micrographs to show you this. The pearlite completely transforms to austenite when you heat it above the appropriate temperature, and when you quench the carbon molecules are trapped as an interstitial solid solution in the martensite.

Not only that but forgings of these alloys undergo precisely the same cycle: they are forged in the austenitic condition at elevated temperature, normalised to form ferrite + pearlite so as to allow machining, and then back up to austentising temperature, quench to martensite and temper.

If this idea you attribute to Mr McClung were correct you’d have the same issue with forgings then: you'd have a nice even structure upon forging, but all the carbide would "segregate out" on cooling to ferrite + pearlite, and you'd never redissolve it on subsequent heat and quench heat treatment. Ironically this would put us back on a level playing field again for castings v. forgings - if this theory wasn't so wrong. Surely you can see that?

If you have specific countering evidence on this very issue, please post
it because we've arrived (finally) at the very crux of the dispute.

I’ve put up the "evidence". Where’s the evidence for your (or your mate’s) position?

btw, the strongest bolt-action that author Haas could find
was an Arisaka. It was almost impossible to blow up.
A forged steel action . . .

The weakest too: the “unsafe” Herter’s Plinker .22 Hornet:neener:

[Reyn]

Is someone honestly seeking the truth here or just refusing to accept it?

[Matt-J2]

Every time I see the thread title on the page, I start thinking documents.

After that, having read through this thread, I think of the symbol of the snake eating it's own tail.

[SlamFire1]

btw, the strongest bolt-action that author Haas could find
was an Arisaka. It was almost impossible to blow up.
A forged steel action . . .
From Hatchers’s Notebook : Japanese 6.5 mm Arisaka, “appear to be made of ordinary carbon steel similar to SAE 1085”

The ground zero for some of de Haas comments on the Arisaka came from a P.O. Ackley’s “Vol II Handbook for shooters and reloaders”. Mr. Ackley conducted blowup tests, of forged military actions, and made comparisons. The Arisaka was the strongest.

Read Stuart Otteson’s Book, “The Bolt Action”. After you read Otteson’s book you will understand that the Arisaka breech was extremely strong, because it was designed to be extremely strong. The Japanese created a design which gave superior support to the cartridge case. Creating a better design allowed them to use cheap plain carbon steel as a material, with plenty of safety margin.

The US used nickel steel in both the Springfield and the Enfield, in an attempt to improve on action strength. But chromium and nickel are rare strategic materials. The Japanese were able to design out those additives.

To get back on my soap box, the Japanese action was strong because they designed it to be strong. There are tradeoff’s, but the Japanese did not design this action as a demonstration of “optimial forging properties”, rather, their design goal was to create a strong, safe and simple service rifle.

Putting the materials or the fabrication process before the design is putting the cart before the horse. And an purposeless argument. It is design that creates a strong action.

Surprising to me, was the Japanese heat treat. From Ackely’s book: “it is obvious that this receiver was not only carefully, but even elaborately heat treated”…”Its heat treatment appears to be superior the average Mauser, Springfield and Enfield”….”Differential hardening, such as used on the bolt and firing pin…..”

Does anyone know of any modern actions that use differential hardening?! Maybe the Japanese used their famous sword smiths to heat treat their receivers, eh Gad!

[JohnBT]

The stuff I watch on my new HD tv. If cast is good enough for the CAT 797B it's good enough for me.

I didn't know they have cast frames. They cast these half dozen huge pieces and weld them together. The truck will haul a load of approximately 380 tons.

From the CAT site:

Weights - Approximate

Gross Machine Operating Weight
1375000 lb

Chassis Weight
473600 lb

Body Weight Range
38 000 - 63 000 kg (84,000 - 140,000 lbs)

http://berny79.altervista.org/Documenti/Immagini/Cat797.jpg

[Gewehr98]

How many investment-cast receivers have failed, compared to their forged counterparts?

Akin to counting the number of angels that can dance on the head of a pin, methinks. :scrutiny:

[Boston T. Party]

Thanks for your reply, Daniel.

Not only that but forgings of these alloys undergo precisely the same cycle: they are forged in the austenitic condition at elevated temperature, normalised to form ferrite + pearlite so as to allow machining, and then back up to austentising temperature, quench to martensite and temper.
All forgings?

Are not some-many forged parts quenched directly into
martensite (thus purposely avoiding the pearlite phase)
and then slightly annealed for easier machining?


In the case of this transformation the diffusion distances the carbon travels are pretty small though, and when you heat it up again the carbon just has to diffuse back these same small distances to dissolve into a new and at least equally uniform (if not even more uniform) austenite.
Can you post any micrographs to support that?

Regards,
Boston

[Boston T. Party]

Having spoken to Ron Smith at length about all this at 2008 SHOT,
I am obliged to relay the gist of the conversation here.

Ron termed the overreliance upon forged steel as "Celtic/Druid bullsh*t"
which floored me coming from such a master of forged steel gun parts
and receivers. He said that cast steel receivers (as he pointed to one of his
own M14s at the booth) could be manufactured to be just as strong as forged,
". . . but the problem is keeping your foundry honest" regarding quality of
steel, molds, etc. He explained that cast steel parts need such stringent
quality control (e.g., individual X-raying) that it makes more sense for some
firms to make forged steel parts instead -- not for any advantage in strength
but in reduction of QC costs.

I then asked him if he had the same confidence in his cast M14 as he has
in his forged M14, and replied that he did, especially after testing his cast
M14 to the point of catastrophic failure (and it still held).

Ron and Kevin McClung know each other (I introduced them) and are friends.
Ron expressed sincere respect for Kevin's knifemaking skill and knowledge,
but asked rhetorically "How many rifle receivers has he made?"

When I earlier posted that:

Regarding my cast-steel receiver SA M1, Ron spoke of
the cast steel being the issue vs. the heat-treat.

. . . it turns out that I'd misunderstood Ron's remark years ago in his shop when
he examined my rifle, as he corrected me at SHOT that he was speaking
of Springfield Armory's poor heat-treat vs. the cast receiver itself. This was
my error, which I will retract in both Boston's Gun Bible and in this thread.
I apologize for misreporting that point, and Daniel was entirely correct when he wrote:

Stretching indicates the steel was soft, and that almost certainly has nothing to do with whether it was cast or forged. More than likely a heat treatment issue, or perhaps the wrong steel.


_________________
When McClung emailed me in 2006:

I guess that what I am trying to say is that if you respect me enough to ask me for an engineering opinion on something, at least respect me enough to believe what I tell you.

. . . it was sufficient for me to publish his thesis in Safari Dreams, but it can no longer
stand alone as a pedestal for that thesis. While I personally still prefer a forged steel
rifle receiver over cast, it's appearing that McClung's thesis so far has no outside
engineering and metallurgical support. In the name of thoroughness I will still try find
corroborating evidence for it, but by now it really is time that McClung himself step up
and either successfully defend his own thesis or admit its flaws. Suffice to say that
the first reprinting of Safari Dreams will be modified accordingly.

Meanwhile, I thank Daniel and others here for their effort and patience during their many
informative posts. It's been a most interesting thread.

Boston

[JohnKSa]

Let me be the first to commend you for your very impressive intellectual honesty in re-opening this thread to post this update and also to thank you for the information.

[Boston T. Party]

Thanks, John, it's very kind of you to say so.

Boston

[SlamFire1]

Let me be the first to commend you for your very impressive intellectual honesty in re-opening this thread to post this update and also to thank you for the information.

I'll second this. :D

[TimH]

Let me be the first to commend you for your very impressive intellectual honesty in re-opening this thread to post this update and also to thank you for the information.

I'll second this.

Well I guess I'l third it since I'm the origanal autor of the thread

[Boston T. Party]

Somewhat related to this thread, and interestingly
it regards the failure of a roll-forged barrel because of poor heat-treating.

I've quoted it below, but refer to the tech article for accompanying photos.

The backstory of this KB at:
http://www.thegunzone.com/m1akb.html

Boston

http://www.thegunzone.com/m1akb/762r.html
This polished section shows two features: a longitudinal crack and sulfide inclusions in the steel. The steel used in the barrel appears to be a re-sulfurized steel. The inclusions seen in the figure have been elongated as a result of the forging/rolling of the barrel. They enhance the machineability of the steel. These inclusions are well spaced and reasonably fine sized and do not form any noticeable network to act as a source of the failure. Shown in the top of the figure is an incipient crack. A number of these cracks were examined. The cracks appear to initiate at the surface, dive straight in and then turn to run parallel to the bore axis. The cracks seen in the transverse section, Figure 5, are these cracks as they appear from the end on. These specimens were etched to reveal the microstructure of the steel. This is shown in Figures 7 and 8.

Figure 7: Microstructure of barrel steel showing ferrite/pearlite structure and crack propagating through the ferrite grains Again, a crack can be seen running parallel to the bore axis. The dark areas are pearlite and the white areas are ferrite. These are the two major constituents of the steel. It should be notice that the ferrite forms a coarse network around the pearlite. Also notice that the cracks run through the ferrite. They appear to initiate in one end of the ferrite grain where it meets the surface, propagate down through the grain, follow it along the axis and then go back to the surface where the ferrite grain again surfaces.

Figure 8: Typical microstructure of failed M14 barrel showing elongated grains. A little background on steel; steel is pretty amazing stuff because it so versatile in the properties that can be produced. One of the reasons is the allotropic phase trans*for*ma*tion that takes place when iron is heated above a certain temperature. It changes its crystal structure, the arrangement of atoms. Above this temperature, the austenitizing temperature, it can dissolve carbon. However, as the steel is allowed to cool and the phase transformation occurs the solubility of carbon in iron decreases. Think of making rock candy; as the water is heated, more and more sugar can be dissolved. As the water cools, sugar begins to precipitate out and form solid sugar crystals. In much the same way, this is how steel works. In steel, the way the carbon precipitates (comes out) is largely dependent on temperature and time. Cool it fast and the carbon can't get out fast enough and is trapped in the iron. Cool it very slowly and it can come out uniformly. All the different phases seen in steels are basically governed by this reaction. It largely evidences itself in the hardness and mechanical properties of the resultant steel. The two phases seen in this steel are ferrite and pearlite. The ferrite is nearly pure iron. The pearlite is a combination of two phases that contains most of the carbon, trapped inside. Ideally, one would want a nice uniform grain size and uniform distribution of the two constituents. This results in uniform properties. The steel used in these barrels is rolled from a starting billet to produce a rod which is than bored out to make the barrel. The rolling or forming process causes these grains to become elongated as the bar is deformed from a large diameter to a smaller one. This is normal. The problem with this barrel2 is that the ferrite grains are quite large and interconnected through the pearlite grains. Because ferrite has so little carbon in it, it has roughly the strength of iron. It is the weaker constituent of the steel. Because the grains are large, interconnected and many sit on the surface of the bore, they are prime sites for cracks to form.

"This steel was most likely held at too high a temperature for too long."
That is what happened here. The other factors to consider are that the forces or stresses in the barrel which are tangential, i.e., want to cause radial cracking, are the highest at the bore sur*face and the bore surface is also the location of the stress concentrations at the land and groove interfaces. The ferrite grains are governed by the grain sizes in the steel while it is held at the high temperatures above the austenitizing temperature. This steel was most likely held at too high a temperature for too long. This allowed the austenite grains to grow too large and resulted in the large ferrite grains. Hardness measurements were also made of the sections removed from the barrel; they average out at about Rc 30. This would be typical for this type steel as processed for a rifle barrel. However, hardness measurements don't always pick up the anisotropy seen in this material. In summary, the failure of the M-14 barrel was the result of a poorly formed microstructure in the steel.

There was no evidence of excessive inclusions that would have contributed to the failure. The cause of the observed non-uniformity in the microstructure was most likely due to poor quality control during the austenitizing/rolling operations. The appearance of the microstructure is indicative of a 4xxx high strength low alloy steel. This is certainly an appropriate steel alloy. There should not have been any problems if conventional practices had been followed. Most likely, the effects of the large grain size after processing could have been detected by conducting mechanical property tests on a sample of the barrels prior to machining. The highly deformed microstructure resulting from the anisotropy would result in different mechanical properties depending on whether the test specimen was cut such that it aligned with the barrel axis or was cut transverse to the barrel axis. Higher toughness and ductility would be measured parallel to the axis and lower toughness and ductility for the transverse specimens in this case.

[gvnwst]

Dang, long going thread:what::eek:

[TimH]

Dang, long going thread

[proud papa} Thats my baby [proud papa]

[gvnwst]

I understand your pride perfectly:neener::D

[Boston T. Party]

Since my last post here, I have continued to search for any
supporting evidence for McClung's theory, with no success.
If anything, it gets "curiouser and curiouser".

Up until May 2001, McClung was touting the (investment cast) CZ550 safari rifle.
Not only that, he had planned to rechamber his (investment cast) Ruger #1 from .458 Win to .460 Weatherby.


I ended up with a brand new Ruger #1 Tropical in .458 Win Mag, . . . now I have an Elephant gun. Wheeeee!
Too bad we are short on Elephants here this season...
I think I want to rechamber it in either .460 G&A or .460 Weatherby. Might as well go all the way now.
http://thefiringline.com/forums/showthread.php?t=14463&highlight=ruger
June 4, 2000, 03:50 PM


I recommend the Winchester Safari Classic model 70 or the CZ BRNO 550 (Mauser) . . .
The only drawback to the CZ 550 is the hole in the end of the bolt handle, which can be welded up or filled with epoxy; and the reverse polish safety . . .
http://thefiringline.com/forums/showthread.php?t=63657&highlight=dg
April 14, 2001, 07:32 PM


If you want to have some experimental fun with a no frills big bore, go out and get one of the CZ/BRNO 550 rifles in .375 H&H or .416 Rigby.
http://thefiringline.com/forums/showthread.php?t=65088&highlight=brno+602
May 4, 2001, 06:48 PM


Not a single mention on the entire thefiringline forum about alleged weaknesses in cast steel guns,
much less "carbide dendrites" being "built in failure paths".

Then, between May and July 2001 some unexplained enlightenment had evidently taken place,
with the first appearance of his "carbide dendrite" theory, as posted by then partner Steve Morrison:


Here is the MD Labs take on the issue:
A cast [1911] slide is a nightmare waiting to happen. Castings, especially those with sufficient
carbon content to be hardenable, tend to precipitate the carbides in fernlike dendrites,
rather than allowing even distribution of the carbides throughout the structure.
This causes built in weaknesses. Imagine the dendrites as the perforations in paper, in the
nature of fracture lines waiting to occur after stresses have been exerted on those areas.
Obviously, this is less than desirable in a combat weapon.
http://pistolsmith.com/pistolsmiths/1550-cast-vs-barstock-frames.html#post13843
07-06-2001, 01:19 PM


Had I known back in 2007 that McClung had owned/praised certain
investment cast steel DG rifles (and still owns one, to my knowledge,
a Brno ZKK 602 in .375 H&H which he rebarreled to .505 Burns),
I would have caught the obvious paradox and questioned his theory.

I regret having published it, and will soon update www.javelinpress.com accordingly.
I cannot stand by a theory I no longer believe, especially when I am now
given to wonder exactly when its author first believed in it himself.

Kenneth W. Royce/Boston T. Party

[Dane Burns]

Funny conversation. Glad to see the truth get squared away.

For the record McClung's "505 Burns" was a rebarreled 416 Rigby the I had rechambered and rebarreld from a new rifle. McClung bought that barreled action from me.

When MD Labs starting claiming their most recent polymer paint for firearm finishing was "as durable" as hard chrome I stopped taking anything they said seriously.

Cast and forged? Caspain builds some of the very best 1911 frames and slides (from castings) and AFAIK still hasn't had to replace any. Understanding the stress required of a slide or frame is a helpful bit of info before looking too much farther. I'm still shooting my CZz, Rugers, Winchesters and Caspian slides.

[Boston T. Party]

At this point, I'm curious where McClung dredged up his theory in 2001.
I've not found a whiff of it anywhere else.

Perhaps it's correct only for +0.83% carbon knife steel but he didn't realize that
and misapplied it to 0.40% carbon gun steel.

All these "failure paths" amongst investment cast guns would have shown up by now.

Boston

[migkillertwo]

I keep hearing about forged and cast receivers. Whats the difference & which one is better? Don't they also mill receivers also? Thnaks Tim
I think we're talking about AR-15 receivers. I personally have never heard of a cast receiver for an AK-47, but I have heard of people inadvertently buying a cast-receiver AR-15 from a fun (gun) show.

With an AR-15, its absolutely important to have a forged receiver. Cast aluminum is just too soft and brittle to work as a receiver.

[Boston T. Party]

migkillertwo, the whole thread has been about steel, not aluminum.
Different metals, different properties.

Boston

[SlamFire1]

I really resent the forged fanatics. They read that dendrite crap and then insult me by parroting the uninformed opinions of other forged fanatics.

My most negative experience with a forged fanatic was at Camp Perry. I had just purchased two Springfield Armory receivers at a great price and this forged fanatic just appeared when I left the Springfield Armory building. Maybe he was waiting for me, otherwise I don’t know how he would have known that I had just purchased SA receivers. This rude young man paced me, proceeded to tell me that cast receivers were junk, and just how superior forged receivers were: TRW receivers will last 500,000 rounds, and etc, etc. This person then went into the Bushmaster building where he might have been working. Maybe he got back on the web to express his outrage with the other ignorant idiots of his clan.

Forged fanatics are a sub set of Mil Spec fanatics, neither of which knows the slightest about their subject beyond the large print in glossy advertisements.

Forged receivers can also be crap. Good design, process controls, and quality control are far more important to making a good part than just "forging" it, and this forged receiver shows it.

This forged receiver would not accept four different military bolts. I tried one TRW, two Winchester, and one SA bolt, and they all bound. You could not get the lugs to rotate into battery. And yet, this is the holiest of holies, a forged M14NM receiver! :what:

http://img.photobucket.com/albums/v479/SlamFire/M1a%20and%20Garand%20Receiver%20Pictures/762mmreceiverandTRWboltDSCN0999.jpg
http://img.photobucket.com/albums/v479/SlamFire/M1a%20and%20Garand%20Receiver%20Pictures/762mmreceiverandTRWboltDSCN1000.jpg
http://img.photobucket.com/albums/v479/SlamFire/M1a%20and%20Garand%20Receiver%20Pictures/762mmreceiverSAboltwontfiteitherDSC.jpg
http://img.photobucket.com/albums/v479/SlamFire/M1a%20and%20Garand%20Receiver%20Pictures/762mmreceiverheelDSCN1004.jpg



I will take a good cast receiver that accepts Military parts without lapping, grinding, any day, over a forged receiver like this.

Maybe the Forging Fairy missed sprinkling her pixie dust over this receiver.

[Boston T. Party]

Forged receivers can also be crap. Good design, process controls, and quality control are far more important to making a good part than just "forging" it

Quite true; thanks SlamFire1.

Here is a quote from a very in-depth M14 study, and one which I wish
I'd found in time back in 2007. (bold emphasis mine)

Smith Enterprise, Inc. Receiver Design, Manufacture and Testing

All Smith Enterprise receivers ever made have been out of certified AISI 8620 alloy steel.
About 1985, Smith Enterprise began producing M14 receivers after several months of
planning and evaluation. This included generating its blueprints and engineering
sketches. . . .

Smith Enterprise made its very first receivers by the precision investment casting method.
The raw castings left a large amount of metal that had to be machined away to obtain the
final form. All Smith Enterprise investment cast receivers have been made with virgin bar
stock AISI 8620 alloy steel certified by the supplier and verified by Smith Enterprise.

Then one finished receiver was selected for destructive testing. Scott Medisha was a
witness to this destructive testing. First, ten rounds of 65,000 psi proof test ammunition
were fired. Next, 76,000 psi proof test rounds were fired. After four rounds of 76,000 psi
proof test ammunition, there were some signs of problems but the receiver had not failed.
The cases were seizing in the chamber. Therefore, Scott Medisha went home and
loaded up one round of ammunition. Ron Smith states this cartridge was loaded with a
large charge of Hercules (now Alliant Techsystems) Unique pistol powder and a 175 grain
bullet. Taking suitable precautions, the destruction cartridge was loaded into the rifle
chamber and fired. Scott Medisha achieved the desired result. The receiver failed with a
dull, muffled boom. The cartridge case vaporized, the barrel blew out about two feet in
front of the stock, and the bottom forward one inch of the bolt blew apart, the magazine
blew out of the action and all magazine spot welds gave out. The back of the receiver
gently rolled off to one side. The receiver on both sides behind the locking lugs cracked.
However, the locking lugs on the receiver and the bolt held! The M14 enthusiast should
not turn his nose up at a well-made investment cast receiver.


page 178 on, destructive testing of investment cast Smith Ent. M14
http://www.second-amendment.org/misc/M14_RHAD.pdf


Fake reputations, habits of glib and clever speech, and glittering surface performance will be discovered.
-- President Eisenhower

[Boston T. Party]

A thorough review of my email history with McClung reveals that
even after a lengthy January 2005 exchange about his theory, he
still apparently didn't know that the Brno/CZ rifles were made
from investment cast steel. (Neither did I back then, else I'd
have asked him about the evident ignorance -- or hypocrisy.)

In 2007-2008, pages 2-5 of this thread featured McClung's first challenger
-- Daniel. McClung refused to engage this credible detractor, leaving me
to try to fill the gap. I've spent dozens of hours of research on this, and
have concluded that the entire "dendritic carbides" (McClung phrased it
in reverse) issue stemmed from the knifemaking world and their casting
of high carbon (called "hypereutectoid") steel.

Here's an example of exactly that:
Verhoeven's research demonstrates the source of the fine cementite bands is carbide formers located in the interdendritic regions of a cast hypereutectic steel. These carbide formers are relatively immobile even at short high heats and are nucleating sites for spheroidal cementite growth during heat cycling and forging. So the pattern source is dendritic. (bold emphasis added)

http://forums.dfoggknives.com/index.php?showtopic=10443&st=140

McClung himself admitted the point, which I published in Safari Dreams on page 9/42:
The problem with cast high carbon steel (as opposed to cast titanium alloy} is that the carbides precipitate in dendrites, rather than being evenly distributed throughout the steel as in forged material. (bold emphasis added)

Only once did he use the term "high carbon", thereafter asserted that
all cast carbon steel was subject to "carbide dendrites". Now, of course, I
notice the disparity; back then I did not, sorry.

Once Daniel refuted the notion that such applied to medium carbon
steels, McClung emailed me that:

4140 has plenty of carbon to form carbide dendrites.
Anything hardenable can, under the right circumstances.

I have not found A SINGLE REFERENCE to this issue with the steel used in
modern firearms. Medium carbon gun steels are hypoeutectoid, not hypereutectoid.
As best as I can so far know, McClung's theory simply does not -- cannot -- apply
to receiver steels as 4140, etc. of <0.83% carbon content.

For those of you interested in a good general primer on metallurgy:
Verhoeven's Steel Metallurgy for the Non-Metallurgist (written for blademakers):
This book explains the metallurgy of steel and its heat treatment for non-metallurgists. It starts from simple concepts—beginning at the level of high-school chemistry classes—and building to more complex concepts involved in heat treatment of most all types of steel as well as cast iron. It was inspired by the author when working with practicing bladesmiths for more than 15 years. Most chapters in the book contain a summary at the end. These summaries provide a short review of the contents of each chapter. This book is THE practical primer on steel metallurgy for those who heat, forge, or machine steel.

http://asmcommunity.asminternational.org/portal/site/www/menuitem.2b9d1953d012ee1480a3c01026e110a0?vgnextoid=1f7b2b41ce0f8110VgnVCM100000701e010aRCRD&itemId=


Barring any new information, I must herewith consider the controversy settled.

Although I do not personally gravitate to cast steel firearms, I now think
that publishing McClung's hitherto unsupported theory was unfair
to the manufacturers of such guns. I regret the error, and will
attempt to recover it as best I can.

Boston

[SlamFire1]

In 2007-2008, pages 2-5 of this thread featured McClung's first challenger
-- Daniel. McClung refused to engage this credible detractor, leaving me
to try to fill the gap.

McClung sent you on a Fools Errand.

For ideologues, this is the best position to be in. Get someone else to fight your battles.

[Boston T. Party]

Wondering where else McClung had referred to "high carbon cast steel" in his forum,
a search was made and these two posts were found (bold emphasis added):

Topic: "Dendritic D-2 steel" - what's it?

Cross section analysis will show the dendrite structure of carbides in any high carbon steel casting.
These are the reason Ruger's frames have to be so fat, that dendritic knives don't hold up, and that I won't use cast high carbon steel.

The problem here is that to derive any strength, the carbides must be evenly distributed throughout the steel. This is why PM steels go to such pains to ensure that even alloy distribution is maintained.

When these carbides precipitate out into veins (dendrites) each of them becomes a potential fracture line in the steel.

http://www.tacticalforums.com/cgi-bin/tacticalubb/ultimatebb.cgi?ubb=get_topic;f=8;t=000271;p=1#000001

Topic: Dendritic Cobalt Carbide?

Nearly any high carbon steel, once smelted into an ingot, will exhibit a dendritic cast structure.
Subsequent rolling and forging of the cast steel ingot breaks up and distributes the carbides throughout the structure.

http://www.tacticalforums.com/cgi-bin/tacticalubb/ultimatebb.cgi?ubb=get_topic;f=8;t=000434;p=1#000007


Again and again, McClung refers to "high carbon" cast steel as suffering from dendritic carbides.
OK, fine, nobody is arguing that point . . . because it's irrelevant. Gun receivers are not made from such steel.
How he managed to then assert that medium carbon cast steel similarly suffers has never been explained.

Also inexplicable was his inclusion of Ruger frames into the "high carbon" cast steel class.
Does he truly believe that a Blackhawk frame or M77 receiver is cast from something like O-1 or 1095?
In retrospect, the whole thing is just bizarre.

___________
from SlamFire1:
McClung sent you on a Fools Errand.

It certainly feels like it now.

I will say that I believe that McClung sincerely believed his own theory, at least
up until it was challenged/refuted here in 2008. He wouldn't have allowed
me to publish what he knew (or strongly suspected) was false or incomplete.
(He had also previously posted his theory on his own forum, before 2005.)

Whether or not he still believes it after this evidence is unknown; we no longer
communicate with each other. (I was summarily booted off his forum for criticising
his unsporting offhand 265+yd shot on a 35+mph gemsbok herd bull, and for
mentioning this THR thread and my imploded belief in his cast steel theory.)
If he ever comes to acknowledge himself wrong about all this, he will have an
extremely difficult time admitting it publicly -- knowing him very well as I did for over 16 years.

An illuminating story comes to mind: McClung once used the word "acerbic"
in conversation with me, pronouncing it with a hard "C" as in "akerbic".
I corrected this; it's pronounced with a soft "C". He disagreed, claiming that
"acerbic" came from the same root word as "ascorbic" (as in the acid).
I chuckled, shook my head, and urged him to look up both words in his dictionary.
He flatly refused, saying "Dictionaries have been known to be wrong."

A capstone quote from McClung's (variously fictional?) autobiography:
"From the outset it was clear that, while he [at age 2] enjoyed the praise,
Kevin had scant tolerance for criticism."
-- Dark Genius (1991), p. 28, by Kevin McClung and Stephen J. Rivele

So, all this considered: No, I don't think that he will ever admit error or defeat about his theory.
One thing he and I are no doubt agreed upon -- we both wish I'd never published it.
Ah, well, live and learn.
MORAL: Be wary of single sources for information; confirm from all angles.

"If someone who is a darling of the industry gets challenged here or elsewhere, what's the problem? Their schtik will either hold up or collapse of its own merit once carefully scrutinized. I for one see no reason to harbor sacred cows for any reason."
-- Kevin McClung, from his forum

I heartily agree, and thus hereby make the following offer:

If anybody can provide me conclusive proof that hypoeutectoid (i.e., <0.83% carbon, such as 4140 AISI)
cast steels commonly used in firearm receivers:

1) unavoidably contain (as a result of the casting process) dendritic carbides which act as "failure paths",
2) to the significant detriment of that receiver's tensile strength during normal usage

I will mail such person within 30 days my sincere thanks along with a postal M.O. in the amount of $500.
Not a bad wage for an afternoon's work . . . if you can find it.
I couldn't.

Boston

[Dane Burns]

Hey Boston,
Been a long time since McClung dropped this theory of his and let it float by.

Not to rub salt in the obvious wound but has it ever occured to anyone that while McClung was telling everyone just how good forged steel was and how bad cast steel is, that he makes his knives by stock removal from plate steel and synthetic, glued on handles?

Compare an actual forged Randal # 14 to a ATAK and the answer to that issue is answered very quickly. Having had both knives I don't question the real skill set is in Florida.

[Boston T. Party]

While I respect his pattern steel knifemaking ability, he does not
cast and forge his own material for knives (and certainly not for gun
receivers). McClung has no degree in metallurgy or engineering or science,
yet few can discern that from his ex cathedra pronouncements.

Dane, regarding your rightful credit to the .505/.416 Rigby, I apologize for taking
McClung's word that you had plagiarized the ".505 Van Horn" (which doesn't even
exist, and the .500 Van Horn Express uses a .510" bullet). I believe that you wildcatted
it first (or in unknown parallel development to some unknown originator). There is no
evidence that you willfully "plagiarized" it from another person. I will correct
this in chapter 9 of Safari Dreams.

For those interested in the .505 Burns backstory:

http://pistolsmith.blogspot.com/
http://forums.accuratereloading.com/eve/forums/a/tpc/f/4711043/m/5141090631


____________
During the 2008 debate in this thread, I told McClung that it was incumbent
on him to publicly defend his theory. He refused outright to do so. Well, I'm
not the one who termed his theory as "thesis" -- he did:

The thesis here is that cast steel receivers are inherently less desirable in a Dangerous Game Rifle (DGR) than a properly heat treated forged billet machined steel receiver. Why? Because the cast receivers are not as durable or reliable due to the process they are created with: Vacuum Casting.

A "thesis" inherently requires support from its author:

"a proposition stated or put forward for consideration,
especially one to be proved or maintained against objections"

My $500 offer of 8 July 2010 applies to "anybody", including McClung.
Friends of his are keeping abreast with this thread, so after due time I'm
sure they'll wonder why he didn't cough up the facts to collect the money.

As Daniel once asked, "Where's the 'science'?"

Boston

[Welding Rod]

On a side note, there seems to be an interest in gun parts machined from bar stock. I am not sure what exactly they are calling "bar", but in my industry, "bar" is rolled. Rolled bar stock, or plate, or beam, etc is not necessarly perfect. I have seen some hideous seams and laminations in these types of materials.

Additionally, I would think grain direction could be quite important in a part. I can't imagine it would be a big advantage for a machined from bar stock slide release to be machined with the grain running parallel to the gun's bore axis.

[Boston T. Party]

When I wrote Safari Dreams, I believed that the Brno 602 and CZ 550
Magnum rifles were of forged steel receivers. After publication, I began
to find many reports that they might be investment cast (especially the 550).
Because of the CZ's bargain price, it seemed very likely that they had saved
money through the investment cast process.

de Haas of Bolt Action Rifles wrote in an earlier edition that
he was not sure if the ZKK 602 was investment cast or forged.
Jeff Cooper thought his ZKK "Baby" .460 G&A was investment cast. Etc.

Yesterday I spent a good hour trying to iron it out, with conflicting info.
The CZ website does not specify (though mentioning hammer forged barrels).
A friend got on the phone today:

So I called CZ-USA this morning and talked to the gentleman who answers
questions on the 550 Safari rifles. Lo and behold they are all forged.
"Bolts on a few rifles (not magnums) are cast but all recievers are
forged." But best to email them and get it in writing is my thought.

Although factory reps vary in their technical acumen, I will take this rep's
word on the matter barring definitive countering information.
That the non-Magnum bolts are not forged was likely a source of confusion,
as well as the cast-like appearance of the ZKK 602, which Jeff Cooper
mentioned on page 165 of Fireworks:

". . . that the action frame seems to be an investment
casting, but is so well finished and fitted it is hard to tell."

Thus, McClung's recommendation/ownership of the Brno/CZ rifles for DG
was no paradox to his preference of forged steel receivers.
I regret the misstatement.

The remaining and glaring paradox of his investment cast .458 Win Mag Ruger #1
"Elephant gun", however, has yet to be understood.

Ruger has never produced a forged #1.

Boston

[Boston T. Party]

It's been two months now, and still no takers.
In this economy, $500 is nice coin for proving such a theory.

Will some hungry metallurgist step up?
Unless . . . it cannot be proved . . .

Boston

[Meta]

I won't bother to address any particular individual post with regards to what I am going to say. However, I will direct this at those that are blaming `big greedy corporations' and `profit' for the lower quality guns of today vs the hand-fitted, assembled by a craftsman pieces of years past. First I will dispense with a few myths.

First, a `working man' can buy an average priced rifle or pistol with a few days wages. Can you say that for a 1950's pre-64 model 70 in the 1950's? Not a chance. People also didn't have a dozen pairs of shoes and racks of clothes either unless they were rich, but that's another topic with the same theme.

It took LABOR and lots of it to produce a hand-fitted firearm from forged and machined parts. It still does.

Labor is NOT cheap and it never was. That is why it was SO expensive to buy ANY rifle back then because there was NO castings or MIM or mass production techniques that were anywhere near as efficient as what we have today, not even close.

At least today a `working man' can buy a rifle or pistol that will serve 95% of the shooting population perfectly well, for a few days labor. It will likely last a lifetime of shooting. Not everyone shoots 500 rounds per week! Most shoot a few times per year.

Lastly, if you think there is some massive profit margins in the firearms industry, you're mistaken. Profitable, yes, lets hope so! Maybe they will INVEST the PROFITS that you helped them earn by VOLUNTEERING your money in exchange for a product in research and development so that they can produce a better firearm for less money. Capitalism, it works!

Oh, one more myth. If it were possible to lovingly forge and machine the parts to a rifle or pistol, have it hand fitted and assembled by a craftsman, and have it cost only $500, you should go into business yourself and make a killing selling more rifles and pistols than ANY custom manufacturer. Don't forget the profit after you pay those highly skilled artisans who crafted such marvelous creations that the gun community will just love, all for just $500. After all, each gun probably only has ten hours labor into it, right? $50 per hour sound fair for a highly skilled craftsman?

The fact is that if ANY company could manufacture a better firearm for less money than Savage/Remington/Ruger/Marlin, etc. they would do it. If margins were SO good and it was SO easy to make money, you could tool up and crank out mass produced junk that will hold MOA at 100 yards all day long and only have to mark up (insert huge profit margin number here) minus a little bit to beat up the more greedy evil capitalist corporations. You would be rich and then you could re-distribute the money you stole from those evil, greedy capitalist pigs back to the workers in your collective.

Enough of the sarcasm, it's time for bed.

[Boston T. Party]

Meta, I agree that Capitalism can produce superlative products . . .
but only when the market demands them.

For a Dangerous Game rifle, I can have (in my qualitative order) a:

Ruger M77 African
CZ 550
BRNO ZKK 602
Win M70 Classic Express
Ed Brown M-704 Express
Dakota 76 African Grade
a custom rifle by Ryan Breeding

In that spectrum, to each his own.

My mistake was dissuading readers from even considering the Ruger
due to its (allegedly inferior) investment-cast steel receiver. While I
prefer the CZ and M70 over the M77, that's just me, as the M77 (if
a reliable feeder, as not all of them are) is fine for the budget-conscious safarist.

In business, there is a famous maxim:

"You can have a quality product, excellent service, and low price.
Pick any two."

I continue to urge DG safari hunters to buy the best that they can painfully afford.
For me, in 2005, that was a Win M70 in .416 RM. It did just fine, and still would.
Today, it's a Dakota M76 in .450 Dakota -- not that I really needed one; I just wanted one.
Tomorrow (maybe), it'll be a Ryan Breeding gun in either .470 Mbogo or .505 Burns.

Boston

[surfinUSA]

I'm no metalurgist and I usually won't respond to vampire threads that rise from the dead.

Although I prefer forged guns and believe they are stronger (hey, I'm old enough that this was the case, but I'm intellegent enough to know manufacturing procesess evolve and improve over time), I also know that one of my favorite rifles the FN-FAL began with forged receivers and then supposedly went to cast receivers with no ill effects.

My question is does any major firearms manufacturer use a cast barrel or are they all forged. Also what makes a barrel that is "cold hammer forgered" better than any other quality barrel or is this nothing more than advertising hype?

[SlamFire1]

My question is does any major firearms manufacturer use a cast barrel or are they all forged.
Why cast a tube when steel manufacturers produce hot rolled round bar stock direct from the mill?

http://www.continentalsteel.com/Carbon-Steel/alloy-steel-bars.htm

http://www.alibaba.com/showroom/hot-rolled-steel-sae-4140.html

http://www.acmetals.com/alloy01.htm


Also what makes a barrel that is "cold hammer forgered" better than any other quality barrel or is this nothing more than advertising hype?

That is a difficult question. If you conduct a web search you will find discussions on hammer forged barrels. My only experience is with a hammer forged barrel is on my Ruger M77 Tactical in 308. The barrel is excellent.

I believe hammer forging reduces cost per barrel. However the machine is hugely expensive. Most aftermarket barrel makers are small shops and cannot afford the cost.

[Boston T. Party]

The only thing I've heard about Ruger M77 barrels is that they apparently
wear more quickly than other mfg.
I've not read any actual comparative testing on that point, however.

_________
It's been 6 months since my 8 July 2010 offer, and still no
metallurgist or "materials scientist" has confirmed McClung's "thesis".
It's surprising that such "engineering truths" would be so difficult to corroborate.

Perhaps my $500 offer was not sufficient for such an expert's time?
I'll now raise it to $1000.

Boston

[Boston T. Party]

Although a CZ factory rep stated that the 550 Magnum rifles are forged,
one source believes that the ZKK 602s are investment cast:

When CZ moved . . . in the 1960s, it ceased production of its machined M-98 Mauser clone and designed a new action called the ZKK series, an investment casting.
-- Gregor Woods, Rifles For Africa, p. 357 (2002)

So many conflicting sources about this.

_______________
btw, my vintage Mad Dog knives are for sale:

http://www.thehighroad.org/showthread.php?t=566980
http://www.fundamentalsoffreedom.com/fswforum/index.php?topic=10675.0

Boston

[BrocLuno]

Next time an anti says we are just a bunch of gun loving, stupid, ignorant hicks, I'm whipping this thread out!

A great read everyone, I've really enjoyed it.

I'm right behind you - let them eat this - phew :neener:

I'm also glad that the discussion is getting resolved and the issues being worked out.

Now, for those of you who have not seen any of Mr Hubels creations :what: take a look at some of his threads. Some of his 12 bore rifles are so scary, I would not think of pulling the trigger on one - yet I know they are tested, and tested, and tested with rounds that are truly impressive and make .50BMGs look like toys :eek:

Metal testing does happen around here - and in very short increments - but, oh my :D

http://www.thehighroad.org/showthread.php?t=178655

[Boston T. Party]

I dropped by the CZ-USA booth to speak with somebody knowledgeable about their
rifle production. According to Intl. Sales Mgr. Richard Zapletal, all ZKK-602 and CZ-550
rifle receivers are investment cast. He was quite sure about this, knowing the factory
processes well. He also said that they were very satisfied with investment casting,
and had no quality issues with it.

(Somebody needs to quickly sell off his "carbide dendrite"-ridden investment cast CZ-550. :uhoh:)

Next, I spoke extensively with Product Manager Mark Gurney of Ruger in regards
to McClung's "thesis". Gurney has had much experience at Ruger's Pine Tree investment
casting plant, and detailed to me accounts of testing-to-destruction of Ruger M77 actions
which held up under much higher pressures than some forged bolt-actions. He was
gracious in understanding that I published something in good faith, though in error.
I will be posting his upcoming rebuttal on my website as part of my way of setting all this right.

The larger lesson I learned was to investigate vigorously to learn the facts, vs. taking the view
of only one person -- however self-annointed and stubborn he may be in his opinion.

Kenneth W. Royce

[rbernie]

And, on that note, we'll let the curtain draw to a close on this eight year long debate (especially since most of the original protagonists have long moved on).