Why Are My .45 ACP Cases Too Short?

[Louca]

Last night I was preparing for some shooting with a friend today. Long story shortened, I found out my .45 ACP brass length is, on average, .0085" shorter than the published standard length of a case (0.898"). And it has me wondering why.

The cases I measured have been shot and reloaded many, many, times. And I am willing to believe it is time for some new brass. But how in the world are the cases getting shorter? I full-length re-size the brass every time. I have NOT ever trimmed the cases, nor do I ever de-burr the mouth of the case. I thought, if anything, the case might lengthen over time, but not shorten. Any ideas?

For reference, all cases were fired in a Colt Series 70 Mk IV 1911. Thanks.

Lou

(Apologies to any who read multiple forums since this is also posted to TFL).

 

[jonkit]

short brass

Yeah those rimless pistol calibers tend to shrink after many firings and reloads. I think it's because they head space on the case mouth not the rim. I could be wrong but I've never had to trim them like rifle brass or rimmed pistol brass. I usually just reload 45 acp till the case neck gets thin. I've never had any issues with them being a little short, also shooting out of a 1911.

 

[Sam1911]

Auto pistol cases tend to shorten after several firings, not lengthen the way bottlenecked rifle brass does.

I don't even know any reloaders who bother to check case length on .45, .40, 9mm., and such.

Not a worry. Load 'em and shoot!

 

[KansasSasquatch]

As long as they're between 0.888" and 0.898" you're okay. Load them up and shoot them. You may have to adjust your crimp a bit if you have varying lengths. 0.898" is maximum case length for .45acp. Anything longer than that should be trimmed. And 0.888" is minimum case length, generally you should toss out anything shorter. A little bit shorter and they'll still work but then they aren't headspacing off of the case mouth like they should, which means the extractor is doing the headspacing and you generally don't want that.

 

[Louca]

I don't even know any reloaders who bother to check case length on .45, .40, 9mm., and such.

And I have never bothered in the 30 years I have shot either. But I just got curious. I am not worried these rounds will not work, I just could not understand why, unlike rifle cases, these got shorter.

Not a worry. Load 'em and shoot!

I will do that, sir! Thanks guys.

Lou

 

[Louca]

As long as they're between 0.888" and 0.898" you're okay. ... 0.898" is maximum case length for .45acp.

Thanks, I did not know that.

generally you should toss out anything shorter. A little bit shorter and they'll still work but then they aren't headspacing off of the case mouth like they should, which means the extractor is doing the headspacing and you generally don't want that.

I will do that, appreciate the advice.

Lou

 

[243winxb]

A length of 0.898" may produce better accuracy in some match grade 1911's better than the minimum length .888"

 

[918v]

I don't even know any reloaders who bother to check case length on .45, .40, 9mm., and such.

Many reloaders sacrifice quality for quantity.

 

[Sam1911]

Yup! With everything in life there is a level of "quality" above which things work sufficiently (even perfectly) and below which they don't.

One secret of a happy life is learning to identify that line and not wasting a lot of effort on needless refinement of aspects to orders of magnitude above that line when no benefit can be realized from the exercise.

Of course, some people do find thoughtless zen-like pleasure in pointless tasks. Like measuring your auto pistol brass length.

 

[Hondo 60]

Sam1911 - well said!

 

[jr_roosa]

I have a couple of buckets of .45ACP brass, and I would hate to have to find one that isn't short. Winchester White Box brass is short after the first firing.

Pistol brass stretches on firing without sticking to the chamber walls like rifle brass, so it exchanges length for girth every time you fire it. The sizing die gets you back a little length, but not much, so it just gets shorter and shorter.

This doesn't matter in my guns, so I don't bother measuring after the first time I tried and found out that all my cases were "too short."

If you are really worried, you can pick up a pistol brass stretcher. It's at the hardware store right next to the board stretcher that you use when you cut a board a little too short. Ask the guy at the counter where they keep them.



-J.

 

[wackemanstackem]

I tend to shrink after I shoot and always wondered why.

 

[918v]

Of course, some people do find thoughtless zen-like pleasure in pointless tasks. Like measuring your auto pistol brass length.

Some people's opinion is based on a lack of knowledge or is it something else?

Here is someone who found autoloading case length affects accuracy:

http://www.leverguns.com/articles/taylor/9mm_reloading.htm

I found that consistent case length makes for consistent crimp.

 

[ReloaderFred]

Of the four 5 gallon buckets of .45 acp brass that I have in my shop, not one of them has ever been measured for length by me, and never will be. They still shoot tiny little groups and ragged holes, so there's no point in wasting time on worthless tasks.

I've posted before that in over 50 years of reloading, and well over 3/4 million rounds loaded, I've yet to trim a pistol case, except for about 10 Federal 357 Sig cases that I was experimenting with. I can still outshoot about 90% of the shooters around here, so I'm not about to start measuring and trimming now.

Hope this helps.

Fred

PS: I'm not the worksmith Sam1911 is, but the point is the same.

 

[Sam1911]

Some people's opinion is based on a lack of knowledge or is it something else?

Yes. Surely that must be it.

Nice article. It surely shows just how VERY important the matter is.

If you need to shrink your mechanically rested 25 yard groups by an inch or two, you certainly could start sorting your brass by length. Good to know.

 

[nix4me]

Clean, size, load, shoot.

 

[osteodoc08]

Hmmm. I've never really given pistol brass much thought. So long as it chambers and goes bang, I really don't care.

Rifle brass on the other hand gets trimmed. I guess it all depends on how the round headspaces. Pistol brass not a huge deal. Id rather spend that time shooting and not measuring. Almost 20 years reloading and I can't recall ever measuring an auto case.

 

[243winxb]

Case Length VS Accuracy-Headspacing on the Case Mouth

Good Info. from above link. http://www.leverguns.com/articles/taylor/9mm_reloading.htm

 

[medalguy]

I seem to recall reading somewhere, don't know where, that the constant resizing results in the brass being always pushed back shorter after firing. It doesn't really lengthen after firing any measurable amount. I have no idea if this is correct or not, but it sounded good to me when I read it.

 

[joneb]

If the brass is short, it may help to decrease the COL accordingly.

 

[HighExpert]

If you think about it, how could the brass stretch? You headspace on the rim and the back of the case is held by the slide. Bottle neck cartridges headspace on the shoulder and the neck can stretch. I have also never trimmed .45acp. I even wonder if the chamber in my bullseye guns might be cut a little tight. It is kind of hard to measure.

 

[1911Tuner]

Ahhh...accuracy.

Sorting brass to insure minimal headspace is a worthy pursuit for serious Bullseye competitors who work to shrink theoretical group sizes by a quarter inch at 50 yards, I suppose. Like bencrest shooters, they want to eliminate every mechanical possibility for group dispersion so that their scores are dependent on the shooter's abilities.

For we mere mortals engaged in more practical disciplines, it's not going to make a difference, unless the gun is fired from a sandbag rest...and that's no fun.

I hear of people stressing over a half inch at 25 yards. I can barely see a half inch dot at 25 yards, much less hit it reliably, and I sure can't detect any difference in accuracy with a few thousandths variation in brass length in the pistols that I shoot.

Could I do any better with a 4,000-dollar Bullseye pistol and sorting the brass for length? Maybe...a little. Enough to make or break the score on a stage in an IDPA match or a run at the falling plates? Nah.

 

[918v]

I have found the 45 ACP to be pretty consistent in terms of case length. The 9mm, on the other hand, varies by .020"+.

 

[homatok]

Well---what I am getting out of this disscussion is that Auto pistols headspacing on the cartridge rim is pretty much a myth! Given allowances for manufacturing variances, coupled with case shrinkage it is much more realalistic to accept they headspace on the ogive of the bullet.

 

[Sam1911]

Er, what?

Ok, no the rim of the cartridge on an auto can't set headspace in the chamber because it is no larger than the cartridge walls themselves. Revolver cartridges do, because the rim is larger than the body of the cartridge, so the rims can stop against the mouth of the chambers, and against the ejector star.

Auto pistol cartridges headspace on the case MOUTH. Sometimes they're probably actually being held back against the breech face more by the extractor (which in a way DOES set headspace by the rim) but you'd have to measure a lot of guns very carefully before you could make a definitive statement about whether the extractor-hook-to-breechface distance is greater or smaller than the slop in the chamber caused by a slightly short cartridge case, on "most" guns. In other words, that CAN happen (and in modern moon-clipped .45ACP 625 revolvers or 610s shooting .40S&W, that's exactly what happens) but I don't think it does very often.

In simpler terms, none of these tolerances seems to be greater than the distance the firing pin can travel to set off rounds reliably -- almost ever. So the guns work regardless of whether short cases make headspace a little sloppy or not.

Having the bullet "headspace" the cartridge by jamming into the rifling isn't a good situation. That tends to jam the bullet and make it really hard to extract a chambered live round.

There's now a sticky on the "plunk test" that should give you a good idea of how autos headspace, or help you visualize it a little more clearly. That "plunk" is the cartridge mouth coming to rest against the step at the front of the chamber. If your bullet is hitting the rifling you don't get a "plunk" but more of a thud, and then the bullet tends to be stuck and not extract easily.