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ACP brass doesn't split?


Abilene
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I imagine if I asked this on the SASS Wire I'd get more answers, but probably no better info.  My reloading is not high volume, using a Lee Turret.  I load usually in 50 or 100 round batches, and it always includes filling up MTM racks with 50 each and inspecting before starting.  During the standard operation of slowly spinning the tray under bright lights while looking for cracks, I just never find any in 45acp brass (mine is all mixed headstamp).  Is this because a) the brass is taper crimped which is easier on the mouth; b) case walls are thick; c) pressures usually pretty low; d) it gets lost before being loaded enough to split?  Or some combination?
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Ditto to all above.  I lose maybe one out of 300-500 cases to a split.  And usually those are at least 40 years old, so I have been scrapping out all my Mil headstamps that are before 1990.  Any commercial brass that looks well worn at the extractor groove also.

 

But I've never had a split case cause a failure to extract from a 1911.  I attribute it to just how rugged the 1911 extractor is.

 

Pressures are higher in 45 auto than any of the cowboy rounds.  We don't work the mouth as hard because we taper crimp instead of tight roll crimp.  Case is pretty stout walled by design.  So, some pluses and some minuses for case life there.

 

One of the biggest reasons we don't see lots of splitting of cases is, I believe, that the 1911 chambers are cut MUCH more tightly to the cartridge dimensions than are the very sloppy chambers in Uberti, Marlin and several other manufacturers' cowboy guns!

 

Good luck, GJ

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I did read an interesting article a month or so ago, but forget where.  Anyway, fellow shot a small number of cases until he got tired of running the test.  Factory power jacketed bullet loads.  Measured case length, extractor groove "height", case diameter, rim diameter, case wall thickness at mouth, primer pocket diameter, etc.  At about 20 firings on the cases, they started miking with case length less than minimum.  Cases were "shrinking" length and swelling (slightly) the primer pocket diameter and rim diameter.  More examination of his data shows what was shrinking was the extractor groove height (between rim and the full diameter case above the groove).  Rest of case above the groove neither stretched nor shrank.  The base of the case was taking all the pounding, and shortening and swelling. He kept firing till he got 40 rounds through them, and gave up because no splits and no failures to fire (even though cases were then several thousandths short of minimum).  And primer pockets seemed a little loose at that point.

 

Lessons learned (at least hinted at):

You never need to trim .45 auto cases to length. They get shorter with firings.  (Unless you get one that is too long to chamber check in the loaded round)

The base of the case will give out first, including primer pockets loosening up. 

It's not REAL important to watch for shorter than minimum cases.  They will look ragged or even develop loose pockets before they get to be non-functional.

And, no, .45 auto cases don't split very often, when fired in a 1911 pistol!  Now, fired in rifle chambers may be a problem of a different diameter.

 

Good luck, GJ

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I had a set of practice brass I loaded 25 times. This was small primer brass that I shot only at home. At about 15 times I started getting split cases, about 2% to 4% with each loading. At 25 loads they were pretty beat up. I caught most of the splits when I picked up the brass by shaking 5 in my hand and listening for the split brass ring. Those that got by me I'd catch when I sized them on my 650, soft feel. If I happened to load a split case or if it split when I seated the bullet, it would cycle and shoot no problem.

The 45 ACP does shrink. I found that out when I had a '73 chambered for 45 ACP. One of the problems I had with the rifle was because the bullet actually chambers on the case mouth. Were as extractor on the 1911 holds the bullet against the slide face and it rarely chambers on the case mouth.

JFN

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  • 3 weeks later...

TNPZzfq.jpg

 

I shot this one yesterday, and noticed the split. I banged it with a rock so it wouldn't get reloaded and put it in my bucket. I like to keep the range clean.

 

Wasn't the split I thought happened!

 

I got this !F range brass well down the food chain, I do not know the history, or how many times it has been reloaded. It is Norinco brass from the 90's. 45 AUTO △ 93

 

 

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From the second tiny split to the right (and perhaps another one halfway up case from that), I'd say this brass had been exposed to weather at least a year, then cleaned.  Unfortunately, those kind of conditions make brass pretty brittle, I find.  Never seen one split down that close to the case head/web area, but that type of a split is one that sometimes occurs on old or brittle cases.

 

Good luck, GJ

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I'd bet both rounds that failed as in JFN picture were out of battery discharge due to firing pin hitting a round that was not fully in chamber.  Could be several reasons, but an over-diameter round, dirty chamber would be possibilities.  High primer less so, as those usually fire round safely. The picture does not look like a split-initiated blow-out to me.    The top edge of the failure is too sharp and straight line, like the back end of the chamber.

 

Double charges that I have seen sometimes swelled or blew open the barrel at the chamber, other times just blew grip(s) and magazine apart.

 

JMHO, GJ

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I do not know the history, or how many times it has been reloaded

 

You can usually examine the "slope" in the extractor cut of .45 auto cases and see extractor tip marks, which can be counted and used as a lower-end estimate of the times it has been fired.  Weak loads will sometimes not put a mark on the slope of the cut, though.

 

When you start seeing ejector marks on the base of the case head, those are loads close to or at +P pressures, in my experience.

 

Good luck, GJ

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  • 1 month later...
If it wasn't obvious in my first post above, I was talking about regular brass.  I have segregated my nickled ACP brass over a number of years, loading only the unplated brass.  Well, I decided I could drop my powder charge by 0.3gr and still easily make power factor, so I opted to put the new load in this nickled brass to keep it separate from the 5 or 600 rounds already loaded of the older formula.  300 nickle cases.  First and last 100 went fine, but I had 4 splits in the middle 100!  One I found at the pre-load sorting, and it was the only edge split.  Found another as it split during loading (could feel it), that one was split in the middle.  And two more split in the middle during loading that didn't get caught until afterwards in the cartridge checker.  So I went from never seeing any splits to 4 in an hour, but it took nickle to make it happen.
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