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

[lever-hed]

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.

 

[Gene]

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.

 

[BrentM]

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.

 

[MNbogboy]

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

 

[Gene]

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

 

[lever-hed]

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

 

[dakota1tn]

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.