shoulder bump question (insight needed)

DJ 480

RECON
Full Member
Minuteman
  • Sep 25, 2011
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    ok fellas,
    This is a new one for me and I am seeking some sage-like wisdom. I threw a new 308 barrel on my Origin (Bisley chamber). I had some 1x fired brass from my old barrel so I took an OAL measurement (2.2490) and subtracted .020 (seating depth) and figured I would start load dev at 2.229. After the ladder was all loaded up, I threw one in the chamber just to check cycle, and wouldn't you know I got a hard bolt close (and on the rest I checked). I was like WTF no way I am in the lands! So I drew some sharpie all around the ogive and put it back in the chamber to check....no marks. Then it hit me! maybe the shoulder was too long as they have not been formed to this chamber. so I checked all my match 308 ammo I have from the last barrel. all the ones that read around 1.626 on the shoulder bump gauge are hard to close. So I am guessing that the shoulders are just not far enough back on this brass for the new chamber.

    now the question, besides hard bolt closures any other issues (pressure related?) would be derived from shooting this? I am guessing not and was just gonna use these rounds as a fire-form opportunity.

    Thanks
     
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    now the question, besides hard bolt closures any other issues (pressure related?) would be derived from shooting this? I am guessing not and was just gonna use these rounds as a fire-form opportunity.
    Pull the bullets dump the powder, size your brass so you can run the bolt with one finger, get it right and move on. You can and will gall your bolt lugs, plus how are you going to shoot groups beating on the bolt.....
     
    With a bushing die, you can remove the neck bushing and decapping assembly and size loaded ammo. Make sure its a shoulder bump issue and not a body diameter issue before you get your whole next batch done. I did it with a 20 practical, and ended needing a small base to die make them fit.
    I might try that on a couple see if it works!