Moderator: MudBug
Siringo wrote:The 400 info was what I have developed. However, I had lots of stress on the case head with these loads. The rims where pulled back, brass shaving, ect. Primers looked OK -- but the cases all exhibits signs of being under pressure while the actions was trying to unlock.
I haven't got all my data ready to post yet, maybe by this weekend, but I have recently increased the weight of my bolt carrier. That in combination with the buffer (A2 setup as from Bushmaster), my overall buffer weight is more than 9 ounces. Stock buffer in A2 stock is 5 ounces (+ or -).
I shot some rounds yesterday -resized Speer 400's - with this setup and did not have the rim pulling as before. The heavier buffer seems to retard the opening of the action.
Developing!!!!!!!!
Siringo wrote:Wildcatter -- you are correct in that the bolt seemed to be trying to open too soon. I have not shot anymore 400's, but as in my post, the heavier buffer seemed to help quite a bit.
I was using 25 grs of LG. Velocity was in the 1550 fps range. The heaviest charge I have used was 27 grs. That was about 100 fps faster and the rim bending was not as bad as with the lesser charges -- so your theory would be correct -- I got the bullet out the barrel faster to allow the pressure to drop before the bolt unlocked.
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