Bolt assembly not completely going forward

[Dualspringfields]

Found problem/problems. Extractor spring wore out resulting in there not being enought tension on the extractor pin. Pin was working out. Gas rings catching on the 2 holes on the side of the carrier. Do not know what these holes are called. But it's the 2 holes you see when you open the dust cover. The bolt didn't do this in my BCM carrier and my bolt wouldbn't do it in his carrier. I put his bolt back in his carrier and started moving it back and forth in the carrier. It finally hung up. Replaced rings. Couldn't get it to do it again. Informed friend that he needs to clean the crap out of the chamber. Filthy! Gave him a chamber brush. A clean weapon is a happy reliable weapon.

Thanks for the help.

[GroundtheGear]

Sounds like from what I understand in all the above is we have 1ST, the failure to lock during the "cycle of operation". All good probable causes mentioned above! I'm leaning towards a blown primer chewed up somewhere causing the stoppage. Another culprit that I didnt see/or missed mentioned is a weak or damaged action spring. Restricted buffer assembly movement ( proper buffer? action spring rifle or carbine?) Strange things happen when you start mixing upper & lowers w/ different manufacturers ( mil-spec/ comm.?) 2nd, now a seized bolt. A possible cause for the itch on your head and use of your leatherman tool might be the bolt will not rotate due to a burred or damaged barrel extension locking it up. Good luck! let us know or just buy a Colt! hehe.

[GroundtheGear]

Good deal! I misunderstood. I thought same prob. w/2 sep. bolts?

[Dualspringfields]

LOL. Not my upper anymore. I gave this upper my friend a few months ago. No blown primers. I inspected the chamber and related areas the 2 times this has happened and neither time was there anything like that. I'm with everyone else Definetly sounds like there was some kind of debis obstructing it. Never saw it if it was. 1st time was steel cased 2nd time was brass cased. 2 months apart. Found extractor spring wore out and gas rings needing replaced. Replaced them. Told him if it happens again to take it to our local "AR15" shop. As far as I know it could be his chamber. He still hadn't cleaned. I looked at it last night when he brought it over here and it is a nice dark grey. Since he has had the upper he has never cleaned the chamber. Excuse; Can't find a chamber brush at Acadamy.

[GroundtheGear]

LOL. With that excuse he really meant to say "No one will clean it for me!" And BTW... I replied and didnt realize you solved prob until my post popped up under yours on 2nd page! lol i will never post again lol!

[Dualspringfields]

Your more than likely correct. And your suggestions were all good ones. Thanks for replying.