I was shooting with a buddy who has an AR308 build this weekend and noticed his brass was ejecting almost straight forward (all were between 12:30-1:30 and landing about 3 feet from the ejection port while shooting prone). He said that how it's always shot and has never had any issues with the rifle extracting/cycling/etc. He has an adjustable gas block so we tried to re-tune it. Anyhow...the gas block is an SLR Sentry 7 clamp-on and according to SLR has 15 usable positions, and for this discussion I'll use position 1 as closed and position 15 as wide-open. When we were tuning the gas block positions 1-4 did not allow the rifle to cycle, when we got to position 5 it allowed the rifle to lock back on an empty mag most of the time and ejected the round at 3:00 very limply, about 1 foot from the port, position 6 allowed 100% reliable ejection but would eject almost straight forward as mentioned above. We kept opening the block just to see if anything would change and it did not...everything from position 6-15 ejected almost straight forward. There is a fair amount of scuffing on part of the ejection port opening itself...looks as if scuffing is from the ejecting case and is wearing off the anodizing...but only on the lower rear portion of the ejection port opening. Anyhow...even though the rifle runs 100% reliably it didn't seem normal to me. I have a few 308AR's that are built very similar to his and none have that issue.
He has Maten receivers, a Rubber City Armory BCG, the SLR adjustable gas block, a Faxon 18" barrrel (mid-gas), and shoots Federal GMM 175 grain ammo. Carbine buffer tube with standard 308 carbine buffer/spring.
Any thoughts, suggestions, etc as to what might be causing this would be greatly appreciated.
Thanks in advance!!!
He has Maten receivers, a Rubber City Armory BCG, the SLR adjustable gas block, a Faxon 18" barrrel (mid-gas), and shoots Federal GMM 175 grain ammo. Carbine buffer tube with standard 308 carbine buffer/spring.
Any thoughts, suggestions, etc as to what might be causing this would be greatly appreciated.
Thanks in advance!!!