When did the USMC begin enlarging the gas escape hole in the bolt? He stated that they were small escape hole bolts. Otherwise, I would have said they were USMC bolts.
Please advise,
Emri
Nevermind, I just figured it out. You were only answering the question, not saying they were USMC bolts. The other difference I noted was the SN under the extractor rather than on top.