First post. I am sched for a 3gun match next Weds and Thurs & I'm in a bind.
I have an A2 bushmaster, 20" HBAR. Ran flawlessly til I put on a 16" Elysium Arms barrel, 1:8 w/Wylde chamber. The gas tube is 8" long.
It stovepipes 2-6 rounds per 30 shooting fast pairs. Brass is caught & new round is always partially fed. The new round ends up with a big ding where it strikes and binds on the stovepiped brass. Empty brass is always pointed outward when stuck.
I've tried:
1. Scrub & decopper barrel.
2. Blow out gas tube. I get a strong stream of air from the muzzle. I’ve not checked the gas block for tightness, because,
3. I've fired single round mags 19 times, string of 10 one day, 9 the next. The bcg has locked back 19 times. Means no gas problem, right?
4. #60 o-ring under the ejector. Shot Freedom 55gr reloads, Federal Match 69gr, XM193. No difference with o-ring or type of ammo.
5. Changed the A2 buffer & spring for spring & buffer from new collapsible stock. The A2 buffer is 6" long w/ a shoulder 1 9/16" from the end, spring is 12 3/8" long of .072 wire. The collapsible butt stock buffer is 3 1/4", spring is 10 3/8" long, same diameter wire. Neither buffer has any ID. Made no difference.
6. Shoot 30 rounds slow fire w/original bcg. All brass ejected except #30, roughly 1 o'clock path, landed around my feet out to a couple cases at about 7'. No real pile anywhere, #30 ended up lying on the mag in the chamber. Don't know if that signifies anything.
7. Swap in a different bolt. I couldn't feel any difference in the fit of the gas rings, or the spring tension of the ejector or extractor. Only used the A2 buffer set up when I tried this. Didn't make any difference.
Suggestions greatly appreciated! I really, really could use some help