seating, then OAL changed from lot to lot (M1A)

Discussion in 'Reloading' started by lever-hed, Feb 11, 2013.

  1. lever-hed

    lever-hed Well-Known Member

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    Using 168-gr Sierra MK's. Setting the Lee seating die to a 2.225" oal to ogive, then changed lots without changing seating die and now bullets come out to 2.229-2.230" . I set the die to touch + 1/4 turn more. The press arm is full stroke touching bottom of die. Cal me crazy but what the f.? I realize the lot change but is the bullet seriously off by THAT much with the change in lots? this was going from a 100-ct box to a 500-ct box. In other words, once I changed lots, I have to push the bullet in .004-.005" further... what is normally acceptable difference?
    I did some BTO measurements on the new lot (.629" & .630" consistently on about 20 bullets) I didnt get to measure the old lot since they all got seated. thanks for any input.
     
  2. Gene

    Gene Well-Known Member

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    I check OAL to ogive each time I change lots and then find the new kissing point. Variances could run much more than you describe. Even in the same lot, there will be some inconsistency.
     

  3. BrentM

    BrentM Well-Known Member

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    Agreed. They can change. I measure them all to be sure. My last lot change on Bergers was .003. The bigger difference on those was bearing surface was .010 difference between the lots. I have seen as much as .040 difference though.
     
  4. MNbogboy

    MNbogboy Well-Known Member

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    Last spring I ordered a 6.5-06 8 twist barrel that didn't arrive till Jan of this year...Also after ordering the barrel I ordered a couple hundred 140 Berger hunting VLDs to break in the new barrel and related brass....

    At about 150 down the tube I seemed to be getting real close to a good load at .045 off......Recently I received a second order of two hundred more....Base to ogive measures a full .050 more on an average with OAL length averaging about .030 longer while od is almost a half a thousandth smaller on the new bullets...Needless to say Berger's die change has created a new bullet for me and my load development has been re-initiated.....I am now seeing .005 off to .005 jam working better than the old bullet at 45 off.....

    Obviously we sometimes see a pattern of dimensional change from order to order as the bullet dies change with age...If we only could forecast when the manufacturer is going to make a die change, then we could probably make orders better suited to our personal need....In my case I would have waited and not wasted a $100 dollars on bullets that were one of a kind.

    Randy
     
  5. Gene

    Gene Well-Known Member

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    When I find the bullet I like, I call different vendors searching for the same lot # and then order 1 or 2 K. I usually start with: www.powdervalley.com or

    www.thirdgeneration shooting supply.com
     
  6. lever-hed

    lever-hed Well-Known Member

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    I’m seeing that the oal(ogv) dimension was consistent for my last 15 from box ‘A’ , I was getting 2.225” plus or minus about .0005 sometimes 2.226” oal(ogv)(cartridge length, 308). When box ‘B’ was started, and I made no adjustments to the die, I was getting 2.230” consistently (plus/minus .0005).. So, based on some of your responses, I’m crying over nothing really, it could be worse.. but I still find it crazy that some could be off by as much as .040 (?!).. ok, well I guess I’ll change my tune..
    PS. I have bought .25 cal bullets for the last oh say 5 or 6 YEARS, and never do I find the bto off by more than .001-.002 , those are usually Sierra or Speer and I just cant see it.. oh well..maybe I just won’t worry about it that much and just shoot ‘em!
    Thanks for the feedback, happy shootin. :)
    -Lever
     
  7. dakota1tn

    dakota1tn Active Member

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    As long as you seat the og of the bullet the same distance off the lands and the diamiter isent different it should still shoot the same. I I measure all of mine to be withing one one thousands either side of the depth I want.