Trimming 45acp?

[Forrest r]

IIRC (and thats from a 77 year old mind) I did an experiment many years ago measurung 45 ACP and other semi-auto brass. Some actually shrunk in length after multiply reloadings/firings...

+1 ^^^^^^

Not only will they shrink, but they will also get work hardened.

This causes huge differences in a consistent short start pressure due to differences in neck tension.

It's hard to see the difference at short distances but when you start stepping out to the 50yd line. Small differences in things start to show up.

 

[Skeet 028]

I once got 500 45 cases that had been trimmed to the same length. Wow! They shot so much better...NOT! They may shoot better out at 50 yards...but I doubt I could have proved it. If I'm going to shoot my 45 that far It's only because I don't have a rifle. The fellow that gave 'em to me thought it was gonna be great. he even figured he had wasted a lot of time. He trimmed the whole thousand new cases we split. Only handgun cases he trims now is 9mm Makarov he makes from 9mm Luger...I think. He has more time than money

 

[ameridaddy]

I've trimmed all my straight wall pistol cases - but just once - when I first get the brass, new or fired. I've found more variation in length than I like, even in new brass, so I trim them to SAAMI minimum, toss those too short. The result is a really consistent crimp forever after, without having to fiddle with the dies.

 

[cracker57]

everyone needs the valley in the woods were you don't even look for your brass. I mostly shoot at a range where I pick up my brass and other peoples brass, these come off a cement floor. then every once in a while we get together in the valley and lose our brass. I never trim, I lose it before trimming is needed and I find very few split necks. All my brass is free and I only shoot semi auto.

 

[H Richard]

When I shot a lot of competition, USPSA, PPC, I would pick up my brass (actually only the brass I could find in a short period of time, mine or whatever other was left there). I wind up with many many different head-stamps. Never found one over length.