My last post I was asking about bolt carriers and I took the recommendation offered. As it turned out, my upper came with a bolt carrier group so I passed mine to a freind doing a build. Mine runs like a new lexus while his not so much. The bolt closes typically the first time (not always- sometimes its about 1/4 inch open). When it does close completely upon hand cycling it ejects the shells maybe 2-3 times before the bolt stops 1/4 inch from closing and is stuck where you have to remove the mag and use a screwdriver to pry it open.

The interesting thing is his other store bought ruger ar does the same thing. My first thought was the ammo but its good ammo and his store bought rifle has 2000 + rounds of the same ammo through it. The shells have slight shew marks from the extractor. I ran a chamber bruss through bot and not any change. Any help appreciated..

IDEAS?