9mm brass length - how picky are you?

[barnfrog]

Not sure but I believe this says differently at least regarding 45acp:

How many times can I reload 45 ACP brass? – Florida Reloading

www.floridareloading.com

Interesting article, and seems to bear out the theory @AJC1 proposed, which is that the cases get shorter because the case head is getting peened down.

As far as safety is concerned, he did mention the possibility of slam fires being more likely as the pocket gets shallower.

 

[243winxb]

trim length

SAAMI has standards on minimum chambers & maximum trim length. Both are the same @ .754"

I have found & trimmed 9mm Luger brass longer then the maximum trim length.

 

[dartor]

Back in August I started a similar thread because I wanted to begin trimming 9mm & 45ACP. I ended up not doing so in large part because of comments by @LiveLife and @Walkalong and @GeoDudeFlorida

Three of the best members here, none of them would steer you wrong.

 

[armoredman]

I was going through some data to work up some 9mm Luger loads for the Berry's 124-grain HBFP plated bullets I picked up, and while I was at it decided to check the trim length so I could check all the processed range brass I have. I noticed the Lyman manual says trim-to length is .751", Western (Accurate) says .749", and Hornady and Speer say .744". My Lee trimmer takes cases down to 0.748". When I started measuring brass, I found 0% were as long as Lyman says the minimum length is. Every single one was under .750". About 60% were between .744" and .749", and around 40% were less than .744". There were even some that were under .740". I tossed everything .733" and shorter, and kept the rest, sorting them into .744" - .745" and .746" - .748" groups. From a safety standpoint I think I'm fine since two of the four sources I checked say .744" is acceptable.

I know that consistent brass length is important for consistent crimp, and because 9mm headspaces on the case mouth. Then again, we're talking about 9mm here, not precision rifle ammo. Do most folks even bother going through the trouble of measuring 9mm brass, and if they do, how particular are they about using only cases that are within a thousandth or two of each other? I know I can't adjust my crimp die that finely.

I have never once in 18+ years of loading 9mm trimmed a single one. Ever. Never had an issue.

 

[nettlle]

I have never checked or trimmed any 9mm brass but this thread got me to feeling guilty. Just got done checking a couple hundred of my cleaned 9mm brass. I have no further need to be concerned about trimming 9mm brass. I checked 45 acp cases for the same reason a few years ago and haven't checked a 45acp case since.

 

[Palladan44]

Not picky at all, I never even bother to measure. About 5 random picks in each batch of 100 get plunk tested and that's it. What bothers me most is the Assymetrical bulge they can get from being fired in lord knows how many chambers of various tolerances. (If they're range pickups or acquired in bulk)

If I were to load SD rounds for carry, you ask a good question there on whether that would be worth doing.

 

[Pottimus]

my crap seems fat, not long. I thought the case length gauge would be my buddy.

 

[Hugger-4641]

my crap seems fat, not long. I thought the case length gauge would be my buddy.

We still talking about 9mm??

Case gauge is a must, but I have a G3C with a tight throat and had to reduce coal for it. Even though the rds passed in my Wilson gauge, they wouldn't plunk in the barrel.

 

[higgite]

We still talking about 9mm??

Case gauge is a must, but I have a G3C with a tight throat and had to reduce coal for it. Even though the rds passed in my Wilson gauge, they wouldn't plunk in the barrel.

I had (emphasis on had) a G3C that wouldn't plunk factory Blazer 9mm 124gr JHP ammo. I had to load so short for it, it made me nervous. Didn't have it for long. (no pun intended)

 

[AK Hunter]

I taper crimp my pistol rounds so any case that's too long will get smashed, any case that's too short won't crimp, that makes a necessity to measure length.

 

[lordpaxman]

I taper crimp my pistol rounds so any case that's too long will get smashed, any case that's too short won't crimp, that makes a necessity to measure length.

I find it necessary to have case length the same for roll crimps, but not for taper crimps. Most of my taper crimps are on a progressive and using range brass which by it’s nature has varied lengths, you’ll need to setup the crimp with a longer case but that means shorter cases don’t get flared as much and don’t require as much taper crimp.