I have been shooting centerfire rifles and handloading for several decades but this is my first AR build. I do have an Armalite 5.56 Match so I'm familiar with the function of the AR.
Now to my issue(s), this build is a new 20 inch Monster barrel, a PSA Bcg mated to a BCM upper on top of the lower from the Armalite 5.56 with the A2 stock and standard buffer and spring. I'm using Starline 6.5 Grendel brass sized and fireformed down to 6 ARC, a process that was fairly straight forward. First set of 40 rounds were the initial fireforming, feeding through three differnt mags. was flawless as was chambering and firing. The problem is that about every third round is a failure to eject mostly a stove pipe but a few double feeds. The ejection pattern was basically from 1 to 4 o'clock, but it was hard to tell when shooting by myself and the bench set-up.
I fired the second set of 40 fireforming yesterday basically with the results. The powder charges are middle of the road Hornady gas gun loads with 70 to 95 grain bullets. Is the gun over-gassed? I was advised that the 20 inch barrel with my lower would be fine, is it? The ejector spring has good tension and when a round does eject it does so with authority. Could the extractor be a problem, hanging on to the brass to long?
Rifle is showing some real potential accuracy wise, but need your thoughts on how to correct my problem
Update: I did some of the massaging of the ejector geometry and ran another 35 rounds through the rifle this weekend. First two rounds were abject failures to eject! I thinking I just made things worse but continued to shoot and for whatever the ejection began to improve. The next ten rounds only two FTE's and then ran 15 without an issue! However loaded the last two rounds in the box and of course had another stovepipe. The ejection pattern also looked better. I am waiting on a new monster bolt with the hopes of getting to that complete reliability.
Thanks for all the valuable input from the members.
Now to my issue(s), this build is a new 20 inch Monster barrel, a PSA Bcg mated to a BCM upper on top of the lower from the Armalite 5.56 with the A2 stock and standard buffer and spring. I'm using Starline 6.5 Grendel brass sized and fireformed down to 6 ARC, a process that was fairly straight forward. First set of 40 rounds were the initial fireforming, feeding through three differnt mags. was flawless as was chambering and firing. The problem is that about every third round is a failure to eject mostly a stove pipe but a few double feeds. The ejection pattern was basically from 1 to 4 o'clock, but it was hard to tell when shooting by myself and the bench set-up.
I fired the second set of 40 fireforming yesterday basically with the results. The powder charges are middle of the road Hornady gas gun loads with 70 to 95 grain bullets. Is the gun over-gassed? I was advised that the 20 inch barrel with my lower would be fine, is it? The ejector spring has good tension and when a round does eject it does so with authority. Could the extractor be a problem, hanging on to the brass to long?
Rifle is showing some real potential accuracy wise, but need your thoughts on how to correct my problem
Update: I did some of the massaging of the ejector geometry and ran another 35 rounds through the rifle this weekend. First two rounds were abject failures to eject! I thinking I just made things worse but continued to shoot and for whatever the ejection began to improve. The next ten rounds only two FTE's and then ran 15 without an issue! However loaded the last two rounds in the box and of course had another stovepipe. The ejection pattern also looked better. I am waiting on a new monster bolt with the hopes of getting to that complete reliability.
Thanks for all the valuable input from the members.
