![]() ![]() The constant tension ejector pushes the case forward fully in the chamber then when the round is fired the case is driven rearward against the breech face by the expanding gases. There is a gap between the base of the case and the breech face. Sounds like you have located the problem. I was shooting for simple first, but alas.Īre you using 7.62×51 ammo or commercial 308 Win ? Huge pressure difference, 308 being 12000+ psi higher. ![]() I will discuss pressure with them and get more data points. I loaned them my go/no go and haven’t heard back yet. So their assumption was headspace, I don’t know enough yet to completely agree. They are getting no compression marks on the other type of barrels that have less headspace. 008 more headspace in the problem barrels than the other type they use. They did some rudimentary measuring and found they had roughly. They are currently experimenting with 2 types of barrels. The issue is on their prototypes with a particular type of barrel. They are now working a project to develop a Gen 2 AR10. They have built a considerable number of custom ARs, both 15s and 10s. Also, to make it clear these guys have the barrels and the extensions made separately and mate them up. This is a common problem that people mistake as pressure signs. Lube the bolt and work it with a piece of fired brass. There could just be some trash under it not letting it compress all the way. Yes, it is making compression marks on the casing in the shape of the ejectors. On the ar 15 what is really bad is when you see the ejector not only ding the case head but twist and tear into the case head leaveing a twist rip. All are prior service in the military (spec ops) and have considerable depth of knowledge in use and building of the firearms they sell. We have set up a mutually beneficial relationship, I send new higher end AR purchasers to them and they send gunsmith business to me. They have helped me learn to properly Cerakote and allowed me to even use their facility and materials for free. Just so you understand my interest in helping these guys, they are good people, honest and fair. Too much pressure could be from too tight a neck area, too short a throat, tighter chamber overall, too much powder etc. Too much pressure and a combination of headspace could cause it. The base of the case is marked on the back where it is blown into the breech face correct? This could be from headspace but usually from pressure like others mentioned. OK so I want to understand the problem/issue. Rather it is a red-flag indicator of over pressure. Nevertheless I agree with Jeff that excessive headspace usually doesn’t cause ejector indentation of the brass head. That’s quite a bit for a new high-power rifle. I have been assuming the 0.08″ is the excessive headspace, or head clearance if you talk to certain purists. ![]()
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