2zero6 wrote:I thought they always used the 7.62 bolts from the beginning of the production run to keep cost down. Is there any way to tell between the to with a caliper?
See, that's why I wanted Hoot to clarify. I'm prolly not quite understanding. I designed the bolt. Bushy drew the prints to my spec. and to their production needs. The 7.62x39 has a nominal rim size of .447". The 284 has a nominal rim size of .476" The Russian Short spec would not allow the 284 to seat unto the bolt face, because the 284 is .026" too big. Until we hear for Hoot, I can only guess what he might have meant. But the facts are, we never used the 762 bolt and couldn't have, it's just too small to handle the larger rim. However you can open that bolt up as you can also open the 223 bolt, to except the larger rim of the 284.
I personally have used, on a custom basis, the 762 extractors on the 284 spec bolt, they kinda-sorta work, but you've got to let them slam seat on the case. Easing the bolt down, to the 762 extractor, requires copious amounts of force on the assist, to get the extractor to jump over the rim and thus is no real fun, but if you ruff-house them, you'll not have a problem.
I also do not know about this.."only feed from the magazine"..thing and the .."do not single feed"..thing. The AR Bolt has always been designed to single feed and feeding from the mag has no advantage to the extractor. This is NOT a controlled feed Mauser. The extractor jumps over the rim, when the case headspaces. Feeding from the mag, the rim does not slip under the extractor. However, there are several gents that have broken extractors. This is probably due to the rare instance that something was out of spec, such as, but not limited to, steel or machining specs or some combination thereof or maybe the stars were lined up, crud happens..t
But then again this is just tubular data, for as I said, I am prolly misunderstanding. In the mean time some of this might be helpful for future use..t