Blown Primers

Billl223

Private
Full Member
Minuteman
Nov 5, 2002
221
84
Worcester PA
I've been loading .223 for several years using 77 gr SMK, 8208, and Starline brass. I can't currently get the powder or brass and am trying Norma brass and AR-Comp. My initial trial load resulted in pressure signs and a few blown primers. I had last loaded some 55 gr loads and forgot to reset OAL for the 77 gr bullet. The difference in OAL was about .035". Is this enough to cause the high pressure?
 
OP, changing components means working up again. Brass has a pretty minimal effect, so if you change ONLY that the workup can be maybe a 3-5% reduction in powder charge. Changing powder is an automatic start at the manual minimum for me.