Simple questions


January 14, 2006, 08:38 PM
Does 9mm brass need to be trimmed? I use a factory crimp die and light loads.
If so, how far from normal before they need to be trimmed?

When priming my cases with a Lee Auto Prime tool I notice that some of the primer pockets are "tighter" than others. If the primer goes in with a lot less effort than normal is that a cause for concern?


If you enjoyed reading about "Simple questions" here in archive, you'll LOVE our community. Come join today for the full version!
January 14, 2006, 10:22 PM
I trimmed all my 45 colt brass to uniform length once. I try to keep the same number of reloads on all my brass, so it stays about the same length, case to case. At least for a revolver that headspaces on the case rim, uniform length is more important than exact length. As long as the lengths are uniform, the crimp die (either separate or with the seater) can be adjusted to crimp properly. If the brass length varies a lot from case to case, then the crimp cannot be adjusted to fit. The 45 colt is also roll crimped, which is probably less critical in adjustment anyway. The 9mm headspaces on the case mouth, and is taper crimped, so exact case length may be more important. Sorry, 9mm is too cheap for me to buy, so I don't reload it (yet).

As far as ease of seating the primer, I have different brands of brass mixed together (I don't segregate them), and I do notice differences in how easily the primers seat, but not so much that I'm worried that some are gonna fall out. I don't know if it is related to brand of brass or what. I suppose you could mark pieces of brass that prime more easily, and inspect them after firing to see if they are trying to back out.

Sorry I don't have more definite help,


January 15, 2006, 12:51 AM
You don't need to trim 9mm brass. You'll wear it out before it needs to be trimmed, and besides, 9mm brass is so plentiful there isn't any reason to spend that kind of effort on it. I had so much of it that no one wanted, I took about 5,000 rounds of once fired 9mm brass to the recyclers the last time I sold my unloadable brass, and that was after I stashed about 5,000 rounds of it for future loading.

As for primer seating, some brands will seat tighter than others and primer pockets will be enlarged the more times the case is fired. If you get a case where the primer goes in without any resistance at all, see if you can push it back out by hand. I just hold the case in my hand with a heavy leather glove on and push it into a universal decapping die held in my other hand. If I can push it out without much effort, I put that case in the recycling bin and reuse the primer. I've done this hundreds of times and saved myself from having a problem with the primer falling out in the gun or before the round is loaded.

Hope this helps.


January 16, 2006, 04:25 PM
like Reloaderfred said you don't have to trim 9MM brass. One thing I've noticed though is with mixed brass your overall length will vary just a bit. I've never had a problem with it since it's only a small amount.

January 16, 2006, 08:56 PM
Your 9mm will get shorter as you reload it over and over unless you roll size it. Roll sizing actually grows the brass and within a couple loadings it could need trimmed.

Don't bother trimming it, reload it and shoot it.

If a primer goes in with very little or no resistance set the case aside. Odds are it was made that way and not pressure related but there is no good reason to load it and shoot it when 9mm brass is nearly free.

January 17, 2006, 01:42 AM
darwin -

you didn't mention head-stamp; if your brass is all uniform or scrounged mixed breed.

s&b brass is notoriously stiff. i started with cci primers in s&b cases; a tough combination. have since moved to winchester primers and cases (more than enough fresh win 9mm on the ground at our range to meet my needs) and the primers slip in like butter.

If you enjoyed reading about "Simple questions" here in archive, you'll LOVE our community. Come join today for the full version!