Why don't double action revolvers require a transfer bar ?

JohnKSa · May 25, 2019

It is necessary in the single action and it is due to the short trigger reset. Which is also the reason for the long sear engagement.

In the DA Ruger revolvers, the transfer bar movement is accomplished nearly entirely by cocking the hammer. You have to look really closely to see any movement of the transfer bar when pulling the trigger although there has to be some because it's connected to the trigger.

I see no reason why that same approach couldn't be taken with SA revolvers. It would obviously require a redesign to adapt to the SA Rugers--perhaps increasing the length of the trigger reset, among other things--but there's nothing special about SA revolvers that automatically requires a lot of transfer bar movement during the trigger pull.

You need that transfer bar travel during the trigger press in order for the transfer bar to function as the safety device it was intended to be.

Again, there's no appreciable transfer bar travel during the SA trigger press of a Ruger DA revolver and yet the transfer bar still functions as a safety device, preventing the discharge of the gun unless the trigger is pressed, and dropping out of the way to prevent the gun from firing if the hammer slips off the sear with no finger on the trigger.

Old Stumpy · May 25, 2019

sabbfan said:
Charter arms claims they invented the transfer bar safety on their website, true or not I don’t know, but that’s what they claim.

If they do then they are liars. Iver Johnson introduced it over 100 years ago.
Unless Charter Arms was secretly in business over a century ago and did not tell anyone.

Old Stumpy · May 25, 2019

J-Bar said:
When the hammer is cocked, the Ruger trigger moves rearward a bit, slightly elevating the transfer bar. Elevation continues as the trigger is pulled.

Which makes no difference whatsoever in the trigger pull. The transfer bar is pinned to the trigger and floats in position. Obviously, it will move as you pull the trigger.

Slamfire · May 25, 2019

One of the reasons that revolver manufacturers moved away from the hammer mounted trigger pin was A) peening the hole in the trigger pin bushing in the recoil shield which an ill behaved revolver cartridge can tie up or let hot gases directed toward the hand if pierced and B) they also are conceded to be more likely to break than the frame mounted firing pins. Unlike having no hammer block, a broke firing pin sidelines any revolver.

I like the hammer mounted firing pin, prefer the older S&W's because of that. I called S&W and whined and moaned about the new frame mounted firing pin, asked why they had eliminated the hammer mounted version. The S&W Customer Rep I talked with said S&W was unable to automate the frame milling/drilling for the hammer mounted firing pin. Said milling/drilling the frame took a dedicated machine with a dedicated person.

Hey, could be.

I had the transfer bar break in my Ruger Super Blackhawk. This is a first year stainless model, something I purchased when first introduced.

Breakage of the transfer bar absolutely, positively, makes this mechanism safe from accidental, or intentional discharge. So, I have mixed feelings about transfer bars.

It was an improvement, in terms of safety, over the three screw version

I found an account in the American Riflemen of an owner whose three screw Super Blackhawk discharged in the holster when something hit the hammer. The pistol shot through his thigh. He was miles from anywhere when it happened and was lucky to get back alive.

During the late 1960s and early 1970s, Ruger lost some expensive lawsuits.These lawsuits resulted from injuries (and at least one death). Not being too judgemental, but the litigants obviously had not learned to only load five beans into the cylinder.

I have read every gun magazine that I could find, lots of books, but don't have access to period literature supplied with firearms. However, in everything I have read, going back to 1906 to now, in the American Rifleman, and decades, back to the 1950's, in popular press magazines, I do not remember a period warning about only loading five rounds in the cylinder of a single action revolver. With all the literature that is out there, and not necessarily looking for it, I could have missed it.

(I thought Elmer Keith addressed accidental discharges in "Sixguns", but a quick scan of the index did not help me find it)

So I ask this question: Who was telling the public to leave an empty chamber under the hammer and when. I know there are posters here who have an amazing amount of period documents, so what does the literature supplied with the firearm say? Does it address carrying an empty under the chamber?

I prefer the hammer mounted firing pin, I am of the opinion that a direct strike mechanism is more reliable in ignition than one that transfers energy from the hammer, to a spring mounted firing pin, or a transfer bar, then to the firing pin. I want the absolute most energy available in the system to be used in deforming the primer. I have had enough misfires and hangfires with weak mainsprings to learn that robust ignition systems are important. I am of the opinion that the ignition mechanisms of pistols are weak when compared to rifles which accounts for the number of misfires and malfunctions I have experienced in rimfire target pistols.

Just this week at a Bullseye match, had a discussions with the bud's around me, about how often misfires occur in their target pistols. One bud, said he had a stove pipe/failure to extract/misfire, about one per box of CCI SV. And worse with other brands. And you know, that pretty much mirrors my experience. I had a lot of misfires with rifle match 22lr and have stopped using SK Rifle, SK STD Plus, RWS Target, because of the frequency of stovepipes. The stuff is perfectly fine in a rifle ignition mechanism. All of us Bullshooters agreed that reliable function was something we would trade off for accuracy, as the ten ring is four inches in diameter and even the crappiest of rimfire ammunition will shoot within half that.

Incidentally, cold is bad for ignition. The powder is harder to ignite and the primer is weaker.

jski · May 26, 2019

Of all my revolvers, which includes both S&W and Rugers, the one with the crispest break is my .30 Carbine Blackhawk after I returned it to Ruger for something totally unrelated but asked for a 3 lb trigger pull.

Oh yeah, this is a 2017 Ruger Blackhawk. Definitely not a 3 screw design.

jski · May 26, 2019

Driftwood Johnson said:
No insult intended, but the engineers at S&W have a little bit more experience with this than you, and the fewest moving parts did not turnout to be the 'best' design.

Anyway, this is one my favorite subjects.

It has long been known that a strong impact to the hammer of a revolver could result in an accidental discharge if the hammer was down on a loaded chamber.

'In the beginning' percussion single action revolvers only had two hammer positions. Half cock, which was the position that allows the cylinder to rotate for loading, and full cock. And of course when the gun fired, the hammer went all the way down. There was no 'safety cock' position on single action Cap & Ball revolvers. In other words, there was no cocking notch that allowed the hammer to be pulled back just a little way from the chamber, or nipple as the case may be. Some early Colts had twelve (not six) locking slots on the cylinder so the cylinder could be locked in place without a nipple being exposed to the hammer. The twelve slot idea went away pretty quickly, probably more expensive to produce than just six slots. But most percussion revolvers had an alternate method of keeping the hammer down between chambers with all the chambers loaded.

This is a cartridge conversion cylinder for a Remington Model 1858. So it is not really a Cap & Ball cylinder. On this cylinder, six independent firing pins take the place of the nipples on a C&B revolver. But notice the notches cut into the cylinder cap between each firing pin. The idea is, to safely load six rounds into this cylinder, the hammer nose would be let down into a slot between the firing pins, locking the cylinder in place until the hammer was cocked to fire the revolver. (I never load this cylinder with six rounds, but that is a different story.)

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Colts had little pins set between the chambers, and a hollow in the hammer that would fit over the pins. The cylinder on the left is a Pieta 1860 Army cylinder. You get the idea.

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By the time Colt introduced the Single Action Army cartridge revolver in 1873 a 'safety cock' notch had been added to the hammer. This is the lockwork of a Colt Single Action Army. The upper arrow is pointing to the 'safety cock' notch on the hammer. The lower arrow is pointing to the sear, which is the tip of the hammer that fits into the different cocking notches on the hammer. So in theory it was safe to load a Colt with six rounds, and ease the hammer back to the safety position. In fact, it was soon discovered this was not safe. Notice how thin the sear is. It would not take much of a blow to the hammer to shear off the tip of the sear, allowing the hammer to fall all the way. If the blow to the hammer was strong enough, like for instance the gun was dropped and landed on the hammer spur on a hard surface, there was a very good chance the revolver would discharge. So anyone familiar with a Colt style lockwork never loads all six, the hammer is always let down on an empty chamber. Of course John Wayne once said 'if you think you need six, then load all six'. But what did he know, he was an actor. Anyway, most single action cartridge revolvers made in the second half of the 19th Century, had a similar 'safety cock' notch built into the hammer. By the way, I always refer to the 'safety cock' notch in quotes, because it is really not very safe.

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Fast forward to the 1950s and Bill Ruger introduced his first single action revolvers. Ruger updated the design, replacing all the leaf type springs of the Colt with coil springs, and added a frame mounted firing pin. But the action still had the 'safety cock' notch on the hammer. These revolvers are known as the Three Screw Rugers because like a Colt, there were three frame screws for the moving parts to pivot on.

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Here is the hammer and pawl (hand) of that revolver. You can see there are three cocking notches on the hammer.

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And no transfer bar. The hammer smacks the firing pin directly.

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During the late 1960s and early 1970s, Ruger lost some expensive lawsuits.These lawsuits resulted from injuries (and at least one death). Not being too judgemental, but the litigants obviously had not learned to only load five beans into the cylinder.So in the early 1970s Ruger completely redesigned all their revolvers to include a transfer bar. This photo shows the hammer of a Vaquero at full cock. The transfer bar has risen and is in position to 'transfer' the energy of the falling hammer to the frame mounted firing pin.

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Now let's talk for a moment about less parts being the better design. Here are all the parts inside a modern Ruger, this one happens to be a New Model Vaquero. There are a lot more parts inside a modern Ruger than in the old Colt design. There are even more parts than in the Ruger Three Screw design. This is how many moving parts it takes for the mechanism to work. The part hooked onto the trigger is the transfer bar. When the trigger spring pushes the trigger all the way forward, the trigger pulls the transfer bar down, moving it from between the hammer and the firing pin, so no matter how hard the hammer may be struck, it will not contact the firing pin. When the hammer is cocked, it physically rocks the trigger back, which in turn pushes the transfer bar up, positioning it between the hammer and the firing pin. And yes, since the motion of the trigger is what controls the position of the transfer bar, the tiny amount of trigger motion required to release the hammer from full cock does result in the transfer bar rising a little bit further. It does not really matter, the transfer bar never covers more than about half the firing pin anyway.

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By the way, here is a patent drawing assigned to Iver Johnson for the first transfer bar. Notice the date.

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Iver Johnson put so much faith in their transfer bar design they had an advertising campaign titled 'Hammer the Hammer'.

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Before I move on from Rugers, here is a photo of the transfer bar in the only double action Ruger I own, a GP 100. This is an older one, it was made in 1997. I'll bet the new ones are not much different. The hammer is at full cock, of course there are only two potions, full cock and all the way down. The transfer bar has risen to the 'firing position' so it can transfer the hammer blow to the frame mounted firing pin.

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Double Action Revolvers.

With double action revolvers it became apparent that the hammer had to be withdrawn a bit to open the gun for loading and unloading. This was even true with the double action Top Break revolvers. This is the lockwork of a S&W Double Action 44 Top Break revolver. In this photo the hammer is all the way down, and the firing pin is protruding through the frame.

View attachment 843081

In this view, the hammer has been eased back to the 'safety cock' posiiton, pulling the firing pin back so it will not get stuck in a fired primer under the hammer. Notice the 'safety cock' notch has been engaged by the rear sear underneath the hammer. Generally speaking, with Top Breaks like this, this hammer position was called Half Cock, even though the hammer did not really go halfway back.

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Just for fun, here is the hammer at the full cock position.

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When double action revolvers with side swinging cylinders were designed, it became standard for the hammers to aromatically retract, so the firing pin would retract and not get hung up in the dent of a fired primer.

This is the lockwork of a S&W Model 1899 Military and Police revolver. The part the arrow is pointing to is called the Rebound Lever. The spring at the rear of the Rebound Lever is pushing the hump at the top of the lever against the hammer, wedging the hammer back from the frame slightly. Notice there is a slight space between the front of the hammer and the frame. If the cylinder was open, we would see the firing pin had been withdrawn and the cylinder could be opened without any jamming of the firing pin in a spent primer. This is the normal 'at rest' position of the hammer.

View attachment 843084

In this photo I am keeping the trigger back, as if I had just fired the revolver. The trigger has forced the front of the Rebound Lever down. This allows the hammer to fall all the way. Notice the gap between the hammer and the frame has closed, allowing the firing pin to protrude through the frame and fire a round.

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By 1905 S&W had redesigned the lockwork of their Hand Ejector revolvers. The Rebound Lever was replaced by the Rebound Slide. In this photo the Rebound Slide is the part under the hammer with the patent date on it. This is basically the same way S&W revolvers are made today. The Rebound Slide has a strong coil spring inside that pushes the Slide forward. When the revolver is in the 'at rest' position, the spring shoves the Rebound Slide forward so the hump on top wedges the hammer back. This is the normal position of the lockwork, the hammer is back, not contacting the frame, and the firing pin is withdrawn so the cylinder can be swung open for loading and unloading. At this time, there was no Hammer Block inside S&W revolvers. The only 'safety mechanism' was the rebound slide, forcing the hammer back. In theory it was safe to fully load these revolvers and leave the hammer 'down' on an empty chamber. However a really strong blow to the hammer could shear off the bottom of the hammer where I have drawn a red line, allowing the hammer to fall all the way and possibly discharge the firearm. I have no direct experience with this, but I strongly believe this system was still safer than the old Colt design. I suspect it would take a much heavier blow to this hammer to break something than it would with the old Colt Single Action Army design, just because of the thickness of the cross sections of the parts.

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As a remedy to the weakness of the rebounding hammer, this is the first style of Hammer Block that S&W designed for their double action revolvers very early in the 20th Century. A slot was cut into the side plate and a hammer block made of spring steel was peened into place. In the normal position, the tab at the top of the hammer block positioned itself between the hammer and the frame, so the hammer could not fall all the way. A ramp on the pawl pushed a spring loaded pin sideways as the hammer moved rearward, withdrawing the hammer block into the side plate, allowing the hammer to fall all the way.

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I'm not sure exactly when this second style of Hammer Block replaced the first style, probably in the 1920s. This time the design was simplified, probably to save cost. The Hammer Block was still a piece of spring steel peened into the side plate. The spring loaded pin was gone. Now there was a tab on the side of the Hammer Block that was engaged by a ramp on the pawl. As the hammer moved back, and the trigger moved back, the ramp on the pawl shoved the hammer block into the side plate, allowing the hammer to fall all the way.

This is the style of Hammer Block involved in the incident in 1944 when a S&W Victory Model fell to the deck of a warship and discharged, killing a sailor. I have no information about whose revolver it was, nor how far it fell. The inquiry into the event found that cosmoline inside the gun had probably hardened, causing the hammer block to be withdrawn in its slot, overcoming the spring action of the hammer block. So when the revolver fell on its hammer, and the lower part of the hammer broke, or perhaps the Rebound Slide was crushed, there was nothing preventing the hammer from riding forward and discharging the revolver.

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The Army ordered Smith and Wesson to get to the bottom of the problem pronto. S&W had a large contract to provide revolvers to the Army, and the Army threatened to cancel the contract. Smith and Wesson conducted tests, dropping revolvers onto the hammer spur, and there were enough failures to warrant a redesign. The engineers were called in and within a week the new Hammer Block design was ready. The new Hammer block was a separate piece of stamped steel, riding in a slot in the side plate. A pin on the Rebound Slide pulled the Hammer Block down when the hammer and the trigger rotated back, allowing the hammer to fall all the way. When the trigger was released, the pin shoved the hammer block up in its slot, blocking the hammer from falling all the way. This style of hammer block is still incorporated in Smith and Wesson revolvers today. As with all three of the Hammer Block designs, it is a redundant safety device, only coming into play if the Rebound Slide no longer wedges the hammer back. Notice the hump on top of the Rebound slide is doing its job of keeping the hammer back. There is a small amount of space and the Hammer Block is actually not doing anything. If the parts holding the hammer back should fail, then the Hammer Block will come into play.

Interestingly enough, Victory Models issued before the new Hammer Block design had a V (for Victory) prefix on the Serial Number. After incorporation of the new Hammer Block design they had a SV prefix.

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Thanks for the energy and time such a learned response takes! It was a fascinating read.

BTW, the design with the fewest moving parts being the preferred design (a design analog to Occam's razor) is a general rule but not one without exceptions.

Jim Watson · May 26, 2019

Slamfire said:
I like the hammer mounted firing pin, prefer the older S&W's because of that. I called S&W and whined and moaned about the new frame mounted firing pin, asked why they had eliminated the hammer mounted version. The S&W Customer Rep I talked with said S&W was unable to automate the frame milling/drilling for the hammer mounted firing pin. Said milling/drilling the frame took a dedicated machine with a dedicated person.

My take on it is that you cannot reasonably mold in a through hole or a narrow blind slot. So the MIM lockwork had to be different to avoid post mold machining entirely, automated or manual. I think DJ had pictures of the differences, showing how the current S&W hammer not only has a flat face to hit the frame firing pin, the DA sear is just laying in a recess in the hammer pivoting on a solid boss.

I have not seen a trigger the equal of an old model S&W revolver. The M52, M41, and High Standard autos get close and a Python is quite good, but the old M14 is best. Old model Ruger and transfer bar Charter don't compare. Even a nice rifle trigger, which in modern guns has been called a "self setting single set trigger" does not have the light crisp character of that direct hammer to trigger engagement.

Yes, Elmer Keith did recount the case of a cowhand who loaded six, put his traditional wooden stirrup up on the saddle so he could tighten the girth, and when the stirrup fell off and hit the hammer spur, the SAA went off and shot him in the leg.

A friend shot a Ruger New Model Blackhawk .45 so much that it forged the transfer bar out too thin to bridge the gap. It didn't break, it was just too thin. He took out the transfer bar and filed the hammer to hit the firing pin directly, He used it that way until "Ruger Only" loads cracked the forcing cone of the barrel. He sent it in and Ruger replaced the barrel, all the moving parts, and reblued it. Not free but they did send him $10 change from his estimated payment.

Slamfire · May 26, 2019

Jim Watson said:
Yes, Elmer Keith did recount the case of a cowhand who loaded six, put his traditional wooden stirrup up on the saddle so he could tighten the girth, and when the stirrup fell off and hit the hammer spur, the SAA went off and shot him in the leg.

So Elmer Keith did warn about dropping things on the hammer spur. That is not exactly an industry wide notification, was it put in all the newspapers in all the cities? Probably not.

How commonly known was it that the Colt SAA was dangerous to carry with six rounds in the cylinder? And as I asked before, what did the factory literature say at the time? To state that someone was stupid, because they carried six rounds in the cylinder, in the absence of warning against this practice, is unfair to the person.

In hindsight there are a lot of opioid addicts who would have liked to have known just how addicting those pills were. Where they stupid? What was industry telling them at the time?

Old Stumpy · May 26, 2019

Slamfire said:
How commonly known was it that the Colt SAA was dangerous to carry with six rounds in the cylinder? And as I asked before, what did the factory literature say at the time? To state that someone was stupid, because they carried six rounds in the cylinder, in the absence of warning against this practice, is unfair to the person.

Some things are just obvious unless you are a fool.
You don't stick your hand into a garbage disposal if it's plugged in.
You don't grab a horseshoe with your hand if it's in a hot forge.
You don't smoke in an explosives warehouse.
and
You don't lower the firing pin onto a live cartridge in any firearm.

Jim Watson · May 26, 2019

Slamfire said:
And as I asked before, what did the factory literature say at the time?

The old Haven and Belden book reproduced old literature. An 1880s instruction leaflet prescribed carry in the "safety notch" after loading all six chambers.

Slamfire · May 27, 2019

Jim Watson said:
The old Haven and Belden book reproduced old literature. An 1880s instruction leaflet prescribed carry in the "safety notch" after loading all six chambers.

I assume that was for black powder revolvers.

Some things are just obvious unless you are a fool.
You don't stick your hand into a garbage disposal if it's plugged in.
You don't grab a horseshoe with your hand if it's in a hot forge.
You don't smoke in an explosives warehouse.
and
You don't lower the firing pin onto a live cartridge in any firearm

I think this is fake

But the Russian warnings about selfies are real

Shooters seldom understand the mechanics behind their firearms and few are able to assess such things as mechanical safeties. Many people you would think are mechanically competent are profoundly incompetent. One bud of mine, a Vietnam combat veteran, and Officer, can be taught to assemble a Mosin Nagant bolt, but he can't figure it out on his own.

I have a relative who is a naturally gifted artist. Draws very realistic pictures of anything. He believes anyone can draw. I wish I could, but I can't. But I can fix things, so I am not totally useless.

Jim Watson · May 27, 2019

Slamfire said:
I assume that was for black powder revolvers.

Sorry, it was for the Colt SAA as made 1873 to date. They were still using black powder in the 1880s. The load was shown as 35 grains.

Slamfire · May 27, 2019

Jim Watson said:
Sorry, it was for the Colt SAA as made 1873 to date. They were still using black powder in the 1880s. The load was shown as 35 grains.

At least the Colt had a safety notch. From what I have read it was easily sheared. But if Colt supplied a safety notch, then where did the idea originate that it was common knowledge to carry only five in the cylinder? The argument could be made, that mode of carry is silly, after all, the pistol has a safety notch?

Driftwood Johnson · May 27, 2019

Slamfire said:
I like the hammer mounted firing pin, prefer the older S&W's because of that. I called S&W and whined and moaned about the new frame mounted firing pin, asked why they had eliminated the hammer mounted version. The S&W Customer Rep I talked with said S&W was unable to automate the frame milling/drilling for the hammer mounted firing pin. Said milling/drilling the frame took a dedicated machine with a dedicated person.

Howdy

Hang on because I am going to digress a little bit.

Smith and Wesson has existed for 162 years. Over that time the company has gone through many iterations of advances in machine technology. Indeed, the gun manufacturing companies of the Connecticut River Valley (Colt included) were some of the leaders in the emerging industrial revolution in the mid 19th Century. In this sense, Smith and Wesson's current use of MIM technology is just one more chapter in that story. (No, I don't like MIM parts myself, but that is just because I am an old fussbudget)

Take for example the interior of the frame on this #1 1/2 New Model Tip Up manufactured in 1873. It is clear to me that this frame was milled out with early pattern following machinery. Not a machinist hand turning the cranks on a conventional milling machine and reading the dials for each cut. The work piece was mounted in a fixture, and the operator manipulated handles on a pantagraph type of apparatus. He kept a stylus pressed against a pattern set off from the work piece and as he followed the pattern the machine cut the complex curves needed in the part.

Here is an illustration of such a machine at the American Precision Museum in Windsor Vermont. (yes, Windsor Vermont is on the Connecticut River.)

Here is photo of such a machine being used to cut the recess in a wooden stock to receive the lock plate of a muzzle loading rifle. Just picture the work piece being metal instead of wood.

The building that houses the American Precision Museum today was originally the Robbins and Lawrence Armory and in 1846 the armory was the first place able to produce interchangeable parts on a practical scale. Interestingly enough Horace Smith, Daniel Wesson, and Benjamin Tyler Henry, to name a few, were associated with Robbins and Lawrence before they went on to greater things. If you are ever in New England and want to see the finest collection of historically significant machine tools in the USA, I highly recommend a visit.

https://www.americanprecision.org/

Here is a photo of the interior milling of the frame of a K-38 made sometime in the 1950s. To my eye, this frame was also hollowed out on a pattern following miller. By this time the machine probably resembled a modern Bridgeport, but with a place for the pattern to be bolted down and it would have handles for the operator to grasp to keep the stylus pressed against the pattern. Notice how uneven and crude the toolmarks that have been left behind look. Clear evidence that this part was not made on a modern computer controlled machine, but there was human input. Yes, the machining looks sloppy, but in truth, the floor of this cavity did not need to be perfect, all the moving parts except the rebound slide moved on bosses set slightly above this rough floor.

Now here is a frame made in the 1970s. Notice how smooth the finish is on the floor of the main cavity. The lighting is not as harsh in this photo, but if it was you would see that the tool marks no longer looked random, but there would be smooth tool paths left behind. This tells me this frame was machined on a CNC (Computer Numerical Control) machine.

Before the introduction of CNC Smith and Wesson (and any other firearms manufacturer) used dozens and dozens of dedicated machines and tools that performed only one specific operation. Whatever it was, drilling holes, broaching, stamping, milling, etc, the work flow took bins of frames or individual parts from one machine to the next, so each operation could be be performed at a machine or work station set up for that specific operation. I have a collection of old photos on my hard drive from the 1950s that are fascinating, showing some of these operations.

Anyway, here is a the firing pin area of a Model 14-3 made in 1974. By this time S&W was using CNC technology to cut out most of the frame recess, but the cuts you see here for the firing pin were probably done on a separate dedicated work station.

Model%2014-3%20Frame%20Firing%20Pin%20Area%2001_zpsdhdxjvhp.jpg

This is not the hammer from that gun, but you can see how the long, narrow shape of the firing pin would fit into that long narrow slot in the frame. Note that to assemble this hammer, pins need to be driven into holes and the firing pin is held in place with a rivet.

Now look at the same area on a 686-6 manufactured in 2015. Much simpler machining in the area of the firing pin. Yes, the frame would would probably have to be removed from the CNC machine for the hole for the firing pin to be drilled and the radius surrounding it, unless they have CNC stations capable of machining on several different axes.

Model%20686-6%20Frame%20Firing%20Pin%20Area%2001_zpsudalzl6z.jpg

Here is the MIM hammer for the 686-6. Yes, it is a simple to assemble part. No special tools are needed, no pins have to be driven into holes. A work aid may be needed to pop the double action sear and its spring in place, but the stirrup is easily assembled with no tools.

Driftwood Johnson · May 27, 2019

I never said anyone was stupid.

What I said was: Not being too judgemental, but the litigants obviously had not learned to only load five beans into the cylinder.

No, I don't really know when it became common knowledge not to load six in an old style Colt. I have known it for about 40 years. Before that I cannot say with any certainty.

tipoc · May 27, 2019

Slamfire said:
I have read every gun magazine that I could find, lots of books, but don't have access to period literature supplied with firearms. However, in everything I have read, going back to 1906 to now, in the American Rifleman, and decades, back to the 1950's, in popular press magazines, I do not remember a period warning about only loading five rounds in the cylinder of a single action revolver. With all the literature that is out there, and not necessarily looking for it, I could have missed it.

(I thought Elmer Keith addressed accidental discharges in "Sixguns", but a quick scan of the index did not help me find it)

So I ask this question: Who was telling the public to leave an empty chamber under the hammer and when. I know there are posters here who have an amazing amount of period documents, so what does the literature supplied with the firearm say? Does it address carrying an empty under the chamber?

I can't answer that question in it's entirety but I know that general bit of knowledge has been around for a long time.

In General Julian Hatcher's 1935 book "Textbook of pistols and Revolvers" in his description of the Colt SAA in chapter 3 he writes ..."Never load but five chambers of the cylinder and always leave the hammer DOWN on the empty one." He then continues with advice to not carry the gun with the hammer down between two loaded chambers..."as it starts back too easily and the cylinder then works over until the primer is under the hammer." He also advised against carrying on the safety notch or half cock notch.

That Hatcher felt the need to mention this is because he discusses safety and limitations of all guns he discusses in this book, because it was common knowledge, but like all common knowledge not all knew it and not all folks were intimately familiar with the workings of all firearms.

tipoc · May 27, 2019

Slamfire said:
At least the Colt had a safety notch. From what I have read it was easily sheared. But if Colt supplied a safety notch, then where did the idea originate that it was common knowledge to carry only five in the cylinder? The argument could be made, that mode of carry is silly, after all, the pistol has a safety notch?

Someone mentioned it earlier that the point of the safety notch was to catch the hammer if it slipped the from the thumb while cocking or decocking the revolver. It's also rather delicate. That notch was not built to be a carry position.

Now in "Sixguns", from 1955 first edition, Keith mentions firing pin on an empty chamber more than once as I recall. Here is one instance from the chapter "Slip Shooting, Fanning, Cavalry Guns" the penultimate paragraph in that chapter:

"Single actions are slow to load from a moving horse as you have to...Then you have to pull cartridges from your gun belt, fill the five chambers and let the hammer down on the empty one."

They are slow to load from a standing horse as well, I'll add.

jski · May 28, 2019

Driftwood Johnson said:
Howdy

Hang on because I am going to digress a little bit.

Smith and Wesson has existed for 162 years. Over that time the company has gone through many iterations of advances in machine technology. Indeed, the gun manufacturing companies of the Connecticut River Valley (Colt included) were some of the leaders in the emerging industrial revolution in the mid 19th Century. In this sense, Smith and Wesson's current use of MIM technology is just one more chapter in that story. (No, I don't like MIM parts myself, but that is just because I am an old fussbudget)

Take for example the interior of the frame on this #1 1/2 New Model Tip Up manufactured in 1873. It is clear to me that this frame was milled out with early pattern following machinery. Not a machinist hand turning the cranks on a conventional milling machine and reading the dials for each cut. The work piece was mounted in a fixture, and the operator manipulated handles on a pantagraph type of apparatus. He kept a stylus pressed against a pattern set off from the work piece and as he followed the pattern the machine cut the complex curves needed in the part.

View attachment 843442

Here is an illustration of such a machine at the American Precision Museum in Windsor Vermont. (yes, Windsor Vermont is on the Connecticut River.)

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Here is photo of such a machine being used to cut the recess in a wooden stock to receive the lock plate of a muzzle loading rifle. Just picture the work piece being metal instead of wood.

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The building that houses the American Precision Museum today was originally the Robbins and Lawrence Armory and in 1846 the armory was the first place able to produce interchangeable parts on a practical scale. Interestingly enough Horace Smith, Daniel Wesson, and Benjamin Tyler Henry, to name a few, were associated with Robbins and Lawrence before they went on to greater things. If you are ever in New England and want to see the finest collection of historically significant machine tools in the USA, I highly recommend a visit.

https://www.americanprecision.org/

Here is a photo of the interior milling of the frame of a K-38 made sometime in the 1950s. To my eye, this frame was also hollowed out on a pattern following miller. By this time the machine probably resembled a modern Bridgeport, but with a place for the pattern to be bolted down and it would have handles for the operator to grasp to keep the stylus pressed against the pattern. Notice how uneven and crude the toolmarks that have been left behind look. Clear evidence that this part was not made on a modern computer controlled machine, but there was human input. Yes, the machining looks sloppy, but in truth, the floor of this cavity did not need to be perfect, all the moving parts except the rebound slide moved on bosses set slightly above this rough floor.

View attachment 843445

Now here is a frame made in the 1970s. Notice how smooth the finish is on the floor of the main cavity. The lighting is not as harsh in this photo, but if it was you would see that the tool marks no longer looked random, but there would be smooth tool paths left behind. This tells me this frame was machined on a CNC (Computer Numerical Control) machine.

View attachment 843446

Before the introduction of CNC Smith and Wesson (and any other firearms manufacturer) used dozens and dozens of dedicated machines and tools that performed only one specific operation. Whatever it was, drilling holes, broaching, stamping, milling, etc, the work flow took bins of frames or individual parts from one machine to the next, so each operation could be be performed at a machine or work station set up for that specific operation. I have a collection of old photos on my hard drive from the 1950s that are fascinating, showing some of these operations.

Anyway, here is a the firing pin area of a Model 14-3 made in 1974. By this time S&W was using CNC technology to cut out most of the frame recess, but the cuts you see here for the firing pin were probably done on a separate dedicated work station.

View attachment 843447

This is not the hammer from that gun, but you can see how the long, narrow shape of the firing pin would fit into that long narrow slot in the frame. Note that to assemble this hammer, pins need to be driven into holes and the firing pin is held in place with a rivet.

View attachment 843448

Now look at the same area on a 686-6 manufactured in 2015. Much simpler machining in the area of the firing pin. Yes, the frame would would probably have to be removed from the CNC machine for the hole for the firing pin to be drilled and the radius surrounding it, unless they have CNC stations capable of machining on several different axes.

View attachment 843449

Here is the MIM hammer for the 686-6. Yes, it is a simple to assemble part. No special tools are needed, no pins have to be driven into holes. A work aid may be needed to pop the double action sear and its spring in place, but the stirrup is easily assembled with no tools.

View attachment 843450

So at the end of the day, both S&W and Ruger ended up using the same metallurgic technique for manufacturing: MIM ?

sabbfan · May 28, 2019

Yes they both us MIM, as does Colt and many other manufacturers

CraigC · May 28, 2019

Slamfire said:
How commonly known was it that the Colt SAA was dangerous to carry with six rounds in the cylinder?

Enough so that in addition to the safety notch, Colt produced percussion and cartridge guns with provisions for lowering the hammer between the chambers.

Driftwood Johnson · May 28, 2019

jski said:
So at the end of the day, both S&W and Ruger ended up using the same metallurgic technique for manufacturing: MIM ?

Howdy Again

I don't know if you can make a blanket statement like that.

Ruger used Investment Castings for most of their small parts up to very recently. They were a pioneer in the use of Investment Castings in firearms.

It appears that fairly recently Ruger has started using MIM parts. I don't have any Rugers new enough for me to tear down and inspect the parts to see if they are MIM or Investment Castings. All the action parts inside all my Rugers are Investment Castings.

Smith and Wesson has gone over heavily to MIM parts, replacing most of the machined parts inside with MIM parts.I don't know if you can say that Ruger has stopped using Investment Castings in their parts, or if they are only using MIM parts to replace some of the Investment Casting parts.

You might want to check out this photo essay I did a few years ago comparing the MIM parts in a modern S&W to the machined parts in an older Smith.

https://www.thehighroad.org/index.p...o-a-revolver-made-with-machined-parts.769929/

tipoc · May 28, 2019

CraigC said:
Enough so that in addition to the safety notch, Colt produced percussion and cartridge guns with provisions for lowering the hammer between the chambers.

Well yes on the percussion guns. It was shown earlier in this thread that on the percussion pistols a notch on the cylinder was particularly placed for the firing pin on the hammer to rest in between the chambers. But this was not the case with the Colt SAA (or the many variations and clones that followed from 1873 till now). These were rear cartridge loading guns and the cylinder face is smooth other than the chambers of course.

I quoted Julian Hatcher above on why it is unwise to use the safety notch on the Colt SAA hammer and to place it between the chambers of the cylinder.

CraigC · May 28, 2019

When I sad cartridge guns, I was referring to the 1860 cartridge conversions with 12 notch cylinders.

tipoc · May 28, 2019

CraigC said:
When I sad cartridge guns, I was referring to the 1860 cartridge conversions with 12 notch cylinders.

View attachment 843683

Sorry I missed your intent.

Driftwood Johnson · May 29, 2019

Howdy Again

As far as I know, the Richards Conversions with twelve cylinder stops, such as CraigC posted were relatively rare.

More common were the ones with the standard six cylinder stops such as this one.

As can be seen in this photo, the hammer only has a half cock and full cock notch. No 'safety cock' notch.

So there is no provision on this revolver to safely carry six rounds.

Frame%20Mounted%20Firing%20Pin_zpsi7ncnvli.jpg

When the hammer is down, it is resting directly on the frame mounted firing pin, which in turn rests on the primer of a round in the chamber. Any sharp blow to the hammer would set off a round in that chamber.

I don't know about the Richards Mason conversions or the Open Tops because I don't have one of those, but I suspect the story would be the same about a 'safety cock' notch on the hammer.

Regarding placing the firing pin between the rims of a cartridge Colt, again it will not work. At least not with large calibers. There is so little space between rims that if the hammer is let down with the firing pin between the rims, if there is any rotational force exerted on the cylinder at all, the firing pin will ride up over the rims and be resting on the case head. If enough rotation is provided, it will rest directly on a primer and the bolt will lock the cylinder in place. I have tried. The firing pin would be resting on between the rims on the circle described by the primers. It might work with smaller case heads such as 38 Special, but not with a 45.

As The Duke said, if you think you need six, then load all six. Otherwise it is safer to only load five.

With the hammer at half cock, you load one, skip one, then load four more. Bring the hammer to full cock and lower it on the empty chamber.

Why don't double action revolvers require a transfer bar ?

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