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Thread: trim tolerances

  1. #1

    Question trim tolerances

    What do you consider max tolerances above factory specs before you trim cases? I know it may vary between rifles, but how many thou is a thou too much...if I'm explaining this right. Thanks.
    If you like getting kicked by a mule...then you'll "love" shooting my .458.

  2. #2
    Moderator Paul H's Avatar
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    Cases have a spec length, and then a trim length that is generally 0.010" longer. As soon as I find one case in a lot that is past the trim length I trim the lot of them back to the spec length. Cases don't grow at the same length, so say after 3 firings and sizings you find some cases are 0.012" longer than spec, and others 0.008" longer than spec. I like having all the cases with as close to the same length as possible, and I'd just assume trim them all at once vs. measuring each and everyone to figure which gets trimmed and which doesn't.

  3. #3

    Talking

    I agree Paul. I had some recently that were in that 0.120 range and others that varied. I usually trim all of the same batch like you, whether they need it or not. In the past, I trimmed every time after sizing...I might go back to that, because I noticed my crimp was becoming heavier, almost too much with a slight hint of bulging. This has to raise pressures some, right? The rifle is a lever Win 71 and I was full length sizing, but I'm going back to partial. All my hunting loads will be new brass. Thanks.
    If you like getting kicked by a mule...then you'll "love" shooting my .458.

  4. #4
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    Quote Originally Posted by Paul H View Post
    Cases have a spec length, and then a trim length that is generally 0.010" longer. As soon as I find one case in a lot that is past the trim length I trim the lot of them back to the spec length. Cases don't grow at the same length, so say after 3 firings and sizings you find some cases are 0.012" longer than spec, and others 0.008" longer than spec. I like having all the cases with as close to the same length as possible, and I'd just assume trim them all at once vs. measuring each and everyone to figure which gets trimmed and which doesn't.
    Paul,

    I think you mean the trim length is .010" shorter than the maximum case length. The max case length is the minimum chamber length so that keeps things in tollerance.
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  5. #5
    Sponsor ADfields's Avatar
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    I trim about every 3rd loading unless it's a roll crimped round. I find I get a better crimp if they are all the same.

    Andy

  6. #6
    Member RMiller's Avatar
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    I use lee case trimmers every loading. Quick and easy.
    "You have given out too much reputation in the last 24 hours, try again later".

  7. #7

    Default neck sizing

    I went to neck sizing my .348 cases today. They dropped right into the chamber...no problem. I sized the fired cases to a smidgeon (approx 1/32) above the shoulder. I then measured with a caliper from base to neck/shoulder junction and found 1.835". I measured some cases that I full length sized and they went 1.810, so I was actually setting the shoulder back by 0.025" every time I resized, so that was the reason for the case stretching with the "bright ring" and why the case length was so long in just a couple firings. Trim length is 2.245 and I had so that measured 2.265-70. Now I can get serious about working up a good huntind load/200gr bullets.
    If you like getting kicked by a mule...then you'll "love" shooting my .458.

  8. #8
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    Quote Originally Posted by Maydog View Post
    I went to neck sizing my .348 cases today. They dropped right into the chamber...no problem. I sized the fired cases to a smidgeon (approx 1/32) above the shoulder. I then measured with a caliper from base to neck/shoulder junction and found 1.835". I measured some cases that I full length sized and they went 1.810, so I was actually setting the shoulder back by 0.025" every time I resized, so that was the reason for the case stretching with the "bright ring" and why the case length was so long in just a couple firings. Trim length is 2.245 and I had so that measured 2.265-70. Now I can get serious about working up a good huntind load/200gr bullets.
    I have heard, but don't know for sure, that neck sizing only will improve accuracy. As long as they are going in the same gun there is no need to full length resize. I have to many guns to keep track of that around here.

  9. #9

    Default Lever gun case stretching

    It is a common thing that lever action guns has enough "give" in their actions that you will often get more case stretch, even with standard loads, then with a bolt action rifle. Rear locking lugs are the main reason. I even had a Schultz & Larson bolt action which had rear locking lugs. Though it was beautifully made of good steel, if I pushed the loads, my cases didn't last as long.
    I never let my fired cases go past the standard COL. Keeps me out of trouble.

  10. #10

    Talking

    Makes sense that a lever gun would stretch cases more...one more reason to neck size, as long as they chamber easily. I.m not going to mess with keeping track of number of firings...just trim everytime and be done with it. Neck sizing may improve accuracy some, but in a lever with open sights probably won't be a factor. Thanks.
    If you like getting kicked by a mule...then you'll "love" shooting my .458.

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