.45 ACP - Case Trimming/Bullet Seating Uniformity

[DEKerr77]

*** I've only been reloading for ~2 mos., so please excuse the potential stupidity of this query ***

Reloaders seem fairly consistent in their belief that .45 ACP brass need not be trimmed. My question: does this apply only to fired cases, or to both new (unfired) and fired cases? I ask because I have a couple of boxes of brand new Starline .45 ACP brass, a random sample (25 cases) of which ranges from .892"-.898" in length. I intend to load them with 230gr FMJ, and I'm not overly concerned with accuracy -- these are mostly for plinking and blasting, not match shooting or self defense. However, I'd like to be able to run them through my turret press without needing to fiddle around resetting the bullet seating die with every round. But there's no way to insure consistent depth/COL unless I use cases of the same length, correct? So I'm wondering if I need to trim the cases, or skip it and disregard the +/- .006" deviation between rounds. I'm not intending to load these cartridges hot, so pressure ought not be an issue.

Any thoughts you all might have on the subject are greatly appreciated.

[Bobshouse]

Your bullet seating die will seat the bullet to the OAL length you set it for, so if the brass is a little long or short, your rounds should come out the same length. The only problem you might have is with the crimping die. I set mine for a medium roll crimp, some will be a little greater than others, nothing to really worry about unless your using plated bullets where a deep crimp could cut through the outer copper. In the 10 years that I've reloaded, I've never had a problem and I've never trimmed my .45 brass, new or used.

[Bawanna]

I never trim 45 either. With brand new brass I make a point to debur the case mouth but that's about it.

I use a taper crimp since the 45 headspaces on the case mouth. I use a Lee factory crimp die which works really well.

If you were loading 357 or 44 or something with a bullet cannelure the case length would be a little more critical but even then a few 1000's isn't a lot.

I haven't reloaded in quite a spell, I loaded a whole bunch and haven't shot much. Need to blow the dust off stuff and make some more.

[CJB]

What I learned from the commercial reloading biz:

Generally, pistol brass will split before it "needs" trimming. If you're of the league that can put fifty .45ACP rounds into 1-5/8" (the X-ring) at 50 yards, then you can get anal about things. All the Bullseye shooters I knew, didn't give a diddly about what brass, and picked up whatever they thought was theirs at the end of a match. Those guys were shooting 293 (out of 300) with maybe twenty something X rings.

[Ikeo74]

To repeat what was said earlier, the length of the case +/- has no bearing on the seating die results. The seating plug is set to put the bullet at your pre-set depth and will put the bullet OAL the same on longer or shorter cases.

[DEKerr77]

Thanks for the replies. I do have a Lee Factory Crimp Die, & I love it. I think I'll leave the new brass untrimmed, load a few of 'em & see how (if) they feed. Quite frankly I'm glad to avoid the hassle. My first project was reloading ~250 .223 cases. I'm glad to have the knowledge, but I felt as if the case prep was never going to end.

Hope everyone had a pleasant weekend, & again, thanks for your help.

Sent from my XT1585 using Tapatalk

[marshal kane]

My Speer Reloader's Guide says maximum case length is 0.898" and trim-to length is 0.888" so anything in between is good as far as case length is concerned. As said by others, case length has nothing to do with cartridge overall length (COL), your cases may be longer or shorter (within specs) and your seater die will adjust to any COL desired.

I use a taper crimp seater die so when I crimp FMJs I set the crimp anywhere from just taking the bell out of the case mouth to a slight taper crimp. Case neck tension is enough to hold the bullet in place. If you take a loaded round and push it nose down into you loading bench and it doesn't move, you have enough crimp. If the bullet backs into the case, you need more crimp.

I've been shooting and reloading .45 ACP since the late '60s and have never trimmed a case. They just don't stretch like rifle cases.

[noylj]

Any case that head spaces on the case mouth, like the .45 Auto, needs to be long enough to minimize head space. Increasing head space by trimming the case will decrease accuracy.
Why do folks feel a NEED to trim?
Taper crimps don't need trimming. COL doesn't need trimming. Accuracy really doesn't need trimming. So why trim?
You trim for two reasons:
1) Case exceeds max length
and
2) One feels a need to trim for ROLL crimp consistency (though I have never seen any change in accuracy from trimmed and untrimmed cases).
In the case of .45 Auto, neither need is met, so why trim?
A bottleneck case has the pressure push the shoulder forward and the base back, so the case gets stretched. A straightwall case simply doesn't have a shoulder to push it forward, so it doesn't stretch.
So, have fun trimming your .45 cases and enjoy the loss in accuracy...

[Bills1873]

I've found that that longer straight walled case, such as .357 and 44 mag will elongate some after repeated shooting/ reloading cycles. Shorter ones, 9mm and 45acp for example, not so much. Since the longer cases have a rim, concern is OAL and consistent length for accuracy, no headspace concerns. I've not noticed any measurable stretching of short auto cases, and I measure most of the time.

[noylj]

Bills1873: can't argue with your findings, just that I haven't found that true for my .38 Spl, .357 Mag, and .44 Rem Mag. No case length growth over time--in fact, just like my auto cases, they tend to shrink.
However, as they head space on the rim, trimming doesn't hurt accuracy so it is fine to do--I just haven't found any benefit at ranges of 50 yards and less.
I have been told that .45-70, at higher pressures than trap-door loads, can lengthen, but I have never read any articles mentioning this fact.

[CJB]

When the working of the brass from loading exceeds that of firing, they shrink.

[Bills1873]

When the working of the brass from loading exceeds that of firing, they shrink.

I can agree with that, noylj, CJB. I guess the minimal amount that I've trimmed was because the mixed cases were of different lengths, and I wanted the crimps all in the same place in each groove. I assumed it was stretch, most likely it was manufacturing because I haven't had to trim for awhile. Thanks.

[CJB]

As was said, you'll get mouth splits before you get overly long 45acp.

On the 9mm, its different, as the taper makes it such that you're working brass back toward the head at every loading. Soon you'll have swollen case heads that wont chamber unless you use a modified die and shell holder.

[earle8888]

I can agree with that, noylj, CJB. I guess the minimal amount that I've trimmed was because the mixed cases were of different lengths, and I wanted the crimps all in the same place in each groove. I assumed it was stretch, most likely it was manufacturing because I haven't had to trim for awhile. Thanks.

In my experience...
Mild target loads normally don't need trim.
HOWEVER
Hot loads and first fired brass may need trimming. .. I always check case length after cleaning and before loading.

I've found that that longer straight walled case, such as .357 and 44 mag will elongate some after repeated shooting/ reloading cycles. Shorter ones, 9mm and 45acp for example, not so much. Since the longer cases have a rim, concern is OAL and consistent length for accuracy, no headspace concerns. I've not noticed any measurable stretching of short auto cases, and I measure most of the time.

KL0NR

[marshal kane]

It's because I want all of my straight-wall revolver cases to roll crimp into my cast bullet's crimp groove that I do occasionally check for case length and trim when necessary. I have found that with enough firings that brass cases in .38/.357, .44, and .45 Colt will stretch. YMMV