Carson Engineering 7.62x39 bolt

[tplace]

I was reading about this bolt at http://www.ar15.com/forums/t_3_121/6...ved_today.html and wondered if anyone had any experience with it running a Grendel?

[Adam Lilja]

It's Cason not Carson. Those are the bolts that are in the Grim Arms AR10's I started a thread about a few weeks ago. Have not personally shot them but it looked good in my hand.

[tplace]

Adam thanks for the correction, my dyslexia was flaring up. I was really wondering if the bolt face recess is .136? I think I will try to give them a call.

[LRRPF52]

It's most likely a .124" face depth, which is a departure from Colt's work on the 7.62x39 in the 1980's. With proper tool steel extractors, 9000 series alloy and good metallurgy on the bolt, it should be a good bolt, but would have to be verified.

There are plenty of bolts for the Grendel's .136" recess, and even non 9130 bolts have repeatedly taken a beating in AA's pressure test apparatus when proof loads are fired, without one ever breaking. Proof loads are in excess of 60,000psi.

The only problems we have seen are on outside sourced bolts made from 8620, with bad metallurgy, and non square upper receiver faces that bear uneven load on the bolt lugs against the barrel extension teeth.

Then there have been a few insane hand loads that sheared lugs, but nothing catastrophic. One member loaded 140gr Sierra Game Kings with over 100% case fill AA1680, and wondered why his bolt broke lugs.