Case Trimming

Discussion in 'The Ammo & Reloading Forum' started by starman, May 30, 2009.

  1. starman

    starman New Member

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    Is it always necessary to measure and trim pistol cases? I'll be loading 38spl & 357mag. I've read that lots of rifle loaders do this but not sure how necessary it is for pistolcases. I ordered every thing I need hand load but then someone brought up this trimming subject. I didn't order a trimmer on calipers but will if its needed. Any opinions will be appreciated.
  2. TranterUK

    TranterUK Guest

    I have never had to trim .38/ .357 handgun cases.

    Rifle cases do stretch and as headspace is very important you need to keep an eye on it. The reloading manuals will give the maximum case length, all you need is a good calliper and check them out.

    If they do go beyond the O/l limit dont use them until trimmed.
    Last edited by a moderator: May 30, 2009
  3. zfk55

    zfk55 New Member

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    Actually there is a reason for trimming sidearm brass. The case mouth gets worked every time you fire, die expand for bullet seating, crimping and fireing again. The case mouth gets thinner and thinner as the brass flows forward and the brass gets worked by expanding and crimping..
    You should check for length peroidically and both trim and anneal. Your brass will last a lot longer.

    Latigo
  4. gandog56

    gandog56 Member

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    I have some .38 special been reloaded 20-30 times. Haven't needed trimming yet.
  5. DWARREN123

    DWARREN123 New Member

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    I have done 38spl, 357 mag, 380 acp, 32 mag, 9mm, 40 s&w and 45 acp and never had to trim the cases.
  6. starman

    starman New Member

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    Thanks guys for clearing this up.
  7. BobMcG

    BobMcG Well-Known Member Supporting Member

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    Measure samples of your brass on occasion. Are they within acceptable limits? Do the case mouths look healthy?

    You won't experience much metal flow from the base toward the neck with run of the mill .38 target ammo and just a little from high power loads. Even with full power .357mag loads the flow seems to be negligible but does occur, they slowly stretch. I have trimmed batches of these before, not because they wouldn't chamber properly, but because I no longer found them to be acceptable. As zfk55 mentioned, this makes the mouths of the cases thicker and healthier again.
  8. buck460XVR

    buck460XVR New Member

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    I don't always trim pistol brass. On new brass for hunting loads I will to keep the crimp consistent, so accuracy is not sacrificed, but normal plinkin' brass no. I do tend to check case length and trim the .460 cases as they tend to grow more than the others.
  9. Hunter X

    Hunter X New Member

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    My specs for 30-06 say 2.494 inches But I will let them get to 2.5 inches.. I don't think that 6 thou is making a difference.. Any opinions on that?
  10. Zhurh

    Zhurh Active Member

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    My biggest problem is taking too much off, I try to keep them close as I can to max. If I let them .006 over max, I'd hardly never trim a case, ha. I'd like to know that too?
  11. gdmoody

    gdmoody Moderator Supporting Member

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    I personally trim them back to the 2.484 that the manuals call for, but that is just me. I use one of the Lee cutters and trim length gauge so it is impossible for me to take too much off!!
  12. Hunter X

    Hunter X New Member

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    I use a Lee Trimmer too. I have it set for the correct length, but how much time do you spend making sure they are not a thou or two or in my case 6 thou over..... Maybe Ill just start trimming them no matter what, just to make sure. I have never encountered a problem yet, and I guess I never want too.... lol
  13. Orin

    Orin Member

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    Keep your brass in lots of 50/100, however you use it. That way each lot will be the same within its group. Don't just throw it all in a bin, to intermix. If it come time to trim, do the lot. Look carefully for splits.
  14. David8989

    David8989 New Member

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    depends on what kind of rounds i'm making. Rifle brass I always trim. Plinking pistol rounds that im not quite as concerned with pinpoint accuracy and i'm building in bulk then I dont trim but low volume precision rounds I do.
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