Thanks guys. I'll try to swap uppers/lowers with him next time we go shooting. I think the recoil spring could be weak, although I'm not sure.
I've since installed a YHM Phantom compensator so I'll see if that affects how it shoots. Also the problem is mostly muzzle rise, and I don't know if the buffer spring being weak could cause that.
And for my barrel, it's a heavy barrel. Not pencil thin or light like a lot of barrels.
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