case gague vs caliper

[wastedimage]

Hello,


I was wondering what exactly does a case gauge measure? Is it just the length of the cartage or are the neck and other demonsions included. Reason I'm asking is I already have a nice set of calipers so I'm wondering if I really need to invest in any..Aside from maybe speeding up the process I'm not seeing what they would do for me.

Thanks

 

[jfh]

1. If you are thinking of the flat stamping with various LOAs notched out--well, that one obviously does (case) LOAs only, and it's a go / no-go check. Because I shoot straightwall handgun almost exclusively, an LOA case gauge is really of little value to me--i.e., those cases shrink, in my experience, and I can get LOA info with the caliper.

2. OTOH, a MAX cart gauge--typically a cylinder machined to maximum cartridge dimensions in several areas, and probably cut to the maximum LOA--does show variance to several specifications, from cartridge LOA, case LOA (at least, if the case is stretched), rim diameter, rim thickness, neck diameter, case base diameter, bullet bulge, and crimp. As one gains experience in using it, you can read the resistance that may show up. If the cartridge doesn't drop smoothly, the feel and timing of the drag will indicate whether or not you have sufficient crimp, a bulged case, or an expanded rim, for example.

Using a barrel chamber, at least in semi-autos, can kind of do the same thing--but the MAX cart gauge is built to industry specs for a given round, NOT the criteria the manufacturer selected for that particular firearm model's chamber.

Personally, I find a MAX cart gauge kept at the bench to be invaluable, at least up to .223. Even with my standardized recipes, I use it as a double-check for settings before I begin a run.

I'll refrain from commenting about larger-rifle-sized checking; that's knowledge I do not yet have.

Jim H.

 

[loadedround]

I have been reloading for over 40 years and do own and know how to use a set of quality calipers and a micrometer. Having said that, I have never needed or owned a case gauge. However thay are extremly handy to check case length and to insure that that your particular cartridge will chamber in your pistol or rifle. Case gauges are an easy way to check for chambering problems quickly, but can get rather expensive if you load many different calibers. I would reccomend case gauges for newer reloaders shooting semiautos in 223 or 308 and loading military cases however to insure chambering. YMMV.

 

[fguffey]

Bottle neck cases: the case gage measures from the shoulder back and from the shoulder forward, this information is at best 'nice' to know if the length and head space of the chamber is not known, I make both gages and use one or the other as a 'transfer', unless I am sizing cases for a chamber I do not have, A reloader should be sizing cases for the chamber the case will be fired in.

Caliber type gages: as long as DATUM is a line and not understood to be a circle/round hole the accessory add on for the dial caliper will have a market.

Again: I have a M1917 Eddystone with .016 head space, when a case if fired in that chamber the case will protrude from the gage .011 thousands, when sizing cases for that chamber I adjust the die and shell holder to avoid moving the shoulder back more than .002 thousands, meaning I have a long chamber in that rifle, the additional length (.016) is between the shoulder of the chamber and the face of the bolt, remedy? I add the .016 thousands to the length of the case not from the shoulder forward but from the shoulder back, back to the gage, I can still use the neck length portion of the case gage to determine the length of the neck from the shoulder forward.

Some expensive trimmers are designed to trim from the shoulder forward with no consideration given to the length of the case from the shoulder back to the head of the case, then there are those that measure case length with no consideration given to the two factors that control case length and do not know if trimming 'trim to' is necessary.

F. Guffey

 

[fguffey]

dial caliper, Caliper type gages:

sorry about that,

F. Guffey

 

[Walkalong]

Case gauges are nice, but not absolutely needed to reload. I went many, many years without one.

I have two now. One in 9MM because I have a tight chambered 9MM pistol (EMP) now and I check all my sized 9MM brass to ensure it will fit that very tight chamber. (All my other 9mm's will chamber anything the sizer gives me that doesn't look grossly wrong)

I also bought a .223 case gauge, because I had a tight chambered (match chamber) AR, and a few of my old plinking/blasting reloads were causing trouble in it. I got rid of it because I wasn't going to use it to compete, and 1" to 1 1/2" groups at 100 out of my AR is just fine with me anyway.

Set up your dies properly and there is a 99.99% chance you won't have a problem.

If you want to fit rifle brass to your chamber to increase case life, an old Stoney Point (or similar) tool to go with your calipers is a better investment.

 

[wastedimage]

Ah..ok..sounds like i might get one just so i can spot check some cases while i watch tv haha. Any recomendations as to what kind? I looked at the dillon ones and it appears they only do the empty case..Do they make ones that do the case and the fully loaded round?

 

[Walkalong]

Assuming .223, as in your other thread, get this Wilson gauge.

Example in this thread.

 

[Sunray]

Guages measure nothing. They just tell you if a part is within tolerance.

 

[ranger335v]

"I was wondering what exactly does a case gauge measure?

Sunray has it correct. It only tells you if a case is within max and minimum sizes, not a thing about the actual dimensions.

For that, you need a caliper. Dial and digitals types are most popular because they are easy to use and read. AND, you will need to add something like the Hornady LnL case and OAL gage tools to attach to your caliper. With those very accurate but inexpensive tools you get very good measurement capability for your fired and sized cases, and for the reloaded cartridges too.

A micrometer is slightly more "accurate" for its range, usually up to 1 inch, but it's really not needed for much by a handloader, the calipers are usually sufficent.

There is no point to spending more than needed for a reloader's caliper. Any 6" stainless steel dial or digital caliper will do all you will ever need it to do.

All of the reloading company branded calipers seem to be made in the same Chinese plant so paying more for a popular brand name, or a professonal grade tool, is a waste. I got mine years ago when Midway had theirs on sale for $18, today the same one is often available from Harbor Freight Tools for as little as $13, on sale.

 

[rg1]

Here's a few good articles on headspace gauges: important when sizing bottleneck rifle cartridges.
http://www.inlandshooters.net/index.php?contentid=99
http://www.dillonhelp.com/xl650english2/pg29.htm
http://www.realguns.com/archives/035.htm
Other gauges such as made by L.E. Wilson are good for checking loaded rounds especially pistol to make sure they will chamber correctly in your guns.

 

[wastedimage]

Ok..so then whats the point in having a case gauge if you already have a caliper? Sure it makes things ever so slightly easier for some people but why spend the $..

 

[jfh]

Sunray: You are correct; gauges measure nothing. I corrected my earlier post to reflect that point.

Jim H.

 

[Otto]

Ok..so then whats the point in having a case gauge if you already have a caliper? Sure it makes things ever so slightly easier for some people but why spend the $..

A max cartridge gage for straight wall ammo checks: mouth diameter, base diameter, rim thickness and diameter, case and overall length and bullet diameter. Using a caliper would be too tedious and time consuming to do the same. Some people use the chamber of their pistol instead of a gage but not all chambers are cut to SAAMI specs.
My cartridge gage checks four cartridges at once so its very fast compared to others. I can check 100 rounds in no time at all.

 

[dmazur]

Ok..so then whats the point in having a case gauge if you already have a caliper? Sure it makes things ever so slightly easier for some people but why spend the $..

Case gauges for bottleneck cartridges permit checking the dimension from the base of the cartridge to the datum line, which is usually the midpoint of the shoulder.

This is almost impossible to do with a caliper, as there is nothing at the midpoint to rest a jaw against.

As one of the previous links showed, there are usually two flats (or a "step") on the base of the gauge. With a case inserted, the user looks at the position of the case head relative to the two flats. Above the upper one = over-length, and below the lower one = under-length. Between the two flats is supposed to be within SAAMI spec for that cartridge.

However, this doesn't mean it is the ideal length for a particular firearm. Some like SAAMI minimum, or close to it, and for others this can result in working the brass more than is necessary.

The other end is usually set up with another pair of flats to show trim length.

So, the gauges are a quick check when setting up a press, and they provide a way to gauge a dimension on bottleneck cartridges difficult (or impossible) to measure with calipers.

 

[Ol` Joe]

If you are only interested in checking headspace on a bottleneck cartridge you can use a socket from your tool set and caliper Find one that hits about midpoint on the shoulder and measure with it as a gage. The numbers you get won`t be exact but, if a close comparision is all that`s needed such as when setting up your dies, it will do the job.

 

[dmazur]

I won't argue that Wilson gauges are a necessity, as there are obviously a lot of techniques to work around not having one.

For general info, I believe that the difference in flats, or the "step" size, is around 0.006", which (for me) is pretty difficult to see.

So yes, if you have already established a correct cartridge resize length (perhaps by repeated adjustments until your bolt just closes...), you could use a socket / caliper measurement as a reference to re-establish that same die setting.

However, the Wilson gauge is a "drop in" check to see if the resized brass is within SAAMI specs.

I'll agree that this may or may not be useful, depending on your circumstances.

 

[fguffey]

wastedimage, I make my gages, I also use a case gage to measure the effecct head space in a chamber has on the fired case, there are those that do not believe it can be done, others do not know it can be done, I also measure the effect head has on a fired case with out a dial caliper but I do not call datum 'datum' or a line, dautm is a 3/8" (.375) circle/hole on a 30/06, my rifle, chamber, reamer, cases, I make up my own circle holes, I am only intrested in the difference between the length of the chamber and the effect the case has on reducing head space.

One day the straight edge will be discovered by reloaders, years after that they will be introduced to the machinist feeler gage, the automotive feeler gage does not include all the gages between .001 and .010, then the reloader can place the straight edge on the head of the case and measure case head protrusion above the case gage with a feeler gage, and, if the case is sized too short the straight edge can be placed across the case gage and a feeler gage can be placed between the case head and om of the straight, this measurement will indicate the amount of sizing below a go-gage length chamber, in the perfect world that would be .005 or the length of a maximum length size case (factory size)

F. Guffey

 

[fguffey]

between the head of the case and bottom of the straight edge

sorry about that,

F. Guffey

 

[fguffey]

maximum length size case (factory size) is .000.

again,

F. Guffey

 

[Bart B.]

Mr. Guffey, your statements on headspace are confusing and somewhat incorrect.

I have a M1917 Eddystone with .016 head space

The .30-06 cartridge has a minimum head space dimension of 1.940-inch; head space gages ground to this dimension are called "GO" gages and are the SAAMI minimum chamber headspace dimension. The "NO-GO" gage is 1.946-inch, SAAMI maximum for the .30-06. There's also a "FIELD" gage measuring 1.950-inch. If the bolt closes on a FIELD gage, the rifle's unsafe to fire factory ammo in.

If your M1917 really has only .016-inch headspace, there's no way one could chamber a round in it. I think what you meant to say (and should have to prevent confusion to readers trying to learn something) was your Eddystone's chamber has 1.956-inch headspace; .016-inch over minimum but more important, it's .006-inch over the FIELD gage limit. A dangerous situation should someone load a factory round with 1.935-inch case headspace in it then shoot it, the case may rupture.

There's other things you say that tain't necessarily so or absolutely wrong, but it's probably a waste of my time to point them out.

 

[Jim Watson]

In a rifle calibre, the Wilson type gauge shows the cartridge headspace dimension as short, normal range, or long. It also shows case length as short or long. It does not generate any numbers, though. There are gauges with calibrations or usable with caliper or micrometer to read actual measurements if you want them.

In a pistol calibre, the usual product is a cartridge gauge. Some are cut to minimum chamber dimensions, some are made to maximum cartridge dimensions. If a reloaded round won't enter the gauge, it may not chamber in one of the "minimum match chambers" the advertising departments love to promote. Again, it does not give you any numbers to put to the size of the round. But I have read numerous accounts of people miking a reload and finding it in spec for every dimension they can find... but it still won't chamber. They are not measuring the critical dimension or they are not doing it right. A gauge based on the chamber design is a lot more useful. I run all my 9mm and .45 reloads through a Midway or Dillon gauge.

Bart, I think Mr Guffey is talking about headspace as head SPACE. There are standardized specifications for the length of a cartridge from head to the shoulder datum circle and likewise for the chamber. But the difference between the chamber and the cartridge is SPACE between the casehead and the bolt face. Pretty obvious that is what his .016" is. His reloading technique fireforms brass to fit HIS chamber and will not likely lead to case separation. He is not doing anything that loaders of the belted magnums are not told to do routinely.

 

[fguffey]

And without a straight edge stand the case gage with a protruding case head on a flat surface then with a feeler gage measure the gap between the case gage and flat surface, this helps when adjusting dies for sizing.



Bart B. ? there is nothing I covered that a bench rest shooter is not familiar with, there are those that have mistakenly shot 308 W (.388 extra head space) in a 30/06, what did they get? a 30/06 case with a very short neck, there are those that have shot 8X57mm in an 8/06 (.129 extra head space), what did they get? a short neck 30/06, and the misunderstood or flawed experiment by Hatcher? it is said he moved the shoulder forward about? 1/4 inch (sound familiar) .125 thousands and fired 30/06 ammo in the chamber with extra head space with out separating the case body from the case head, what did he get? he got formed cases for his modified chamber, now if Hatcher took those modified cases and sized them back to minimum size and repeated the experiment he would have shortened the life of the case, and the life of the rifle and the life of the shooter, and at the same time there are claims he moved the shoulder forward with a go-gage and the action of the bolt cam, I believe that claim is a blind of two stories.

Back to 'AGAIN' I do not move the shoulder forward by firing, I move the shoulder forward by forming, that is the reason I never pass a bargain on 280 new/used Remington cases, the 280 R shoulder is ahead of the 30/06 shoulder by .041 thousands, so it is a matter of technique, method, skill, knowledge and a few tools and time to form 30/06 cases with a shoulder moved forward .014 to .015 thousands to form a case for the Eddystone with head space, I know head space of the chamber before I size the case, but this is something bench rest shooters learned to do before they became bench rest shooters.

I made a set of gages for the 30/06 and sent them to a collector in Bradford, PA. he called me and informed me he had what he thought was an Eddystone M1917 that had not been issue, except for the .016 head space.

I meant to say .016 head space because that is what it is, .016 thousands and it is beyond the field gage by .002. Keeping up! a factory loaded case from the store is .000, that is .005 under a go-gage chamber, that puts the go-gage chamber at +.005, the no-gage chamber is +.009, the field gage is +.014, or .014 over a factory loaded round or +..009 over a go-gage etc.. that is what I said, the rifle in Bradford PA., has .016 head space, my M1917 has .016 head space IF I shoot factory or full length ammo in it, the advantage to a long chamber? cases fired in it can be sized (not formed) to fit long chambers, like +.008, .010, where do those numbers come from, these numbers can not be obtained from a go-gage or a no-go gage, both are fixed, they either go or do not go, that is good enough for most but I want to know 'by how much' because I cut my chamber using gages that start at -.012 under factory ammo, that is .017 under a go-gage.

I also sent another set to North Carolina, the collector, reloader gun builder called and and asked me how I came up with the technique/method, I asked him if he had a lathe, he said yes, I asked him if he had a mill, he said yes, I then explained to him it was easy, he says he takes a few of the gages with him to gun shows, shops or answering adds, and no one objects, in thinking back I sent him two sets made two different ways.

F. Guffey