I'm tired so I may not be much help right now, but here are a few suggestions. I'm a little unsure of what you're trying to explain so some of these suggestions probably have nothing to do with your problem but oh well.

-Use some better quality, brass ammo
-Try a different BCG if you can
-Check to see if the gas tube/gas block is lined up and installed correctly
-Lube it
-Check the gas rings on the bolt


I just went through a similar problem. Rounds weren't ejecting with Tula. Bolt was coming back enough to scratch the rounds in the magazine though. Went with brass ammo and it would eject but not pick up a new round. It ended up being the gas block about 1/4" off. Hopefully some of that helps.

Sounds better when you say it. Lol

It always sounds better when I say it LOL

I've had issues with Monarch bubbling out the primers, so I know some of that Russian ammo has a reputation for overcharging. I'd put my money ammo or headspacing being the issue. If your ammo length is within spec, and you're using quality ammo, you might need to have the barrel head spaced properly.

Ill give you 100 bucks for it!

I'll give you $100.05 for it.

Gravy hit the nail on the head. Extractor is installed wrong in bolt head. Instead of throwing shell out of chamber through the ejection port, it is throwing empty round against walled side of lower and attempts to er chambered the fired round. I found this out after cleaning my AR and putting extractor to throw shell to the left instead of right. Simple fix....

Tech amber the fired round. Sorry about typo

damn autocorrect. Should read rechamber fired round.

On most AR's I don't even think this is possible since the cam pin can only go in one way on the bolt.

I don't think that explains the problem D.C.Cowboy is describing. If an AR15 was fired with the bolt installed backward (which I'm not sure is even possible; it will only go in one way on any of my bolts), then you would never chamber a second round. You would look down and see a double penetration porn in your ejection port.

I've seen a bolt flipped 180 degrees and the cam pin fit in. Easy to do if not paying attention when cleaning the gun.

I've got a DPMS that will let you install extractor 180 degrees from proper orientation, so I have personally experienced what OP stated. Maybe not all BCG's will let you do this, but I have one