There was a discussion going on on MontanaMarine's other AR post concerning the 7.62x39 in an AR15 breaking the bolt's locking lugs.
The thread was originally about AR pistols and not 7.62x39 in ARs, so I'll post this question here.
It was stated that 5.56 operating pressure is around 62K psi, and 7.62x39 is around 45K psi.
Based on surface area calculated by rim diameter of 5.56 case, at 62k psi, the force on the bolt will be 6,974 lbs.
7.62x39, using SAAMI spec pressure of 45k psi, will have a force of 7,058 lbs. on the bolt.
My question is.....
What about the 6.5 Grendel. Max pressure on it is 52K psi and it has the same .44" (.442" vs .447") rim size as the 7.62x36.
Has there been issues with the Grendel shearing off locking lugs?
