Hey All,
I finally have a follow up to my 308 project questions. I drilled the gas port to 0.081", installed the Armalite EA-1095 spring, and the gas system operates correctly now. I have the gas block set at 1.5 turns out of a possible 3.5 turns, and I get consistent lock-back on the bolt. Yay.
Now I have Failure to Eject issues. I ran 5 rounds of American Marksman 147gr M80 ammo. Each round loaded and shot fine, but none of them ejected. When I cycled the bolt by hand it grabbed the casing and pulled it out, but it never worked during firing. I ran a couple misc rounds as well, and none of them ejected on their own, but all of them ejected by hand. Using the charging handle I can load and eject a live round just fine.
I can see where the extractor pawl has grabbed and pulled on the rim of each casing, tearing a little bit of the brass away. It appears that the casing is getting stuck in the chamber during firing (casing expansion?), but when dry firing the casing can slide out easy enough. I checked the headspace with rented gauges when I put everything together, but I wonder if the chamber is too tight/too small diameter.
I also noticed marks running across the sides of casing of both fired and unfired rounds after I chamber them. They are about 1/4" long, and run perpendicular to the axis of the shell casing. I get 2 or 3 marks each time I chamber a round. Could this be from a rough chamber bore? Does it need to be reamed?
Your thoughts are much appreciated.