Ok, so I just finished my SBR and first shot out the gun the BCG stuck on ejection, ripped the case head off leaving the casing in the chamber, caulked it up to either bad chamber or cheap steel ammo. Fast forward to a few minutes ago when I tried to cycle the weapon with a loaded mag.

BCG cycles fine without rounds but as soon as you put a loaded mag into the weapon and chamber a round, its goes to battery fine, trying to eject the round is very difficult, difficult to the point of having to tap on the CH with hammer to eject the round. Tried a separate BCG thinking bad chamber but the other BCG cycles fine with rounds in the mag so its down to the BCG, probably down to the bolt. So any ideas guys.

sounds like bolt/bcg issue, probably out of spec bolt causing head spacing issue

did you swap the bolts in the bcg and try that, maybe narrow it down the bolt.

Need a little more info. Did you build it yourself, buy the upper, or have it assembled at a smith? It sounds like either a barrel/barrel extension head spacing issue or a BCG issue.

Edit: Just actually finished reading your entire post . Already ruled out the barrel and extension in your first post. I would try swapping the bolts and carriers. That should narrow it down to what is out of spec.

I think the shoulder on ammo may be long, or you may have a tight chamber.

Sounds a little ghey

Any unusual marks on the sticky bolt carrier group?

Lube the sh#t out of it and hand cycle a couple hundred times. Slicken things up a bit.

Swapped the bolt between BCGs and had the same problem so it had to be the bolt, more is has to be the extractor, so I used my reloading Micrometer to measure make a few measurements and nothing seemed out of spec but the back nub of the extractor just looked to tall, so I got out the old lansky knife sharpening kit and honed the nub down a bit, still sticky when cycling through a maf but not near as difficult to cycle, will hone a little more off and try again.

Thanks for all the ideas guys will update if successful.

I would not take this approach. You're talking about a possibly out of spec bolt and with that a possibly nonstandard headspacing with that. I would rather send it back, or just replace it. A new bolt is only $40-70. Here's one for 60.

Headspace is not something I would mess with.

what he said.

Pretty sure it is not a head space issue as the other BCG worked fine and when I swapped the bolts between BCGs it was the bolt that caused the hang up, but to err on the side of caution I took ya'll's advice and have contacted the manufacturer of the BCG to see what they want me to do.

Thanks again guys for the help.

Some bolts are just really tight when new. It's actually the gas ring fit inside the carrier. You can usually tell by taking the BCG out and pushing the bolt into the carrier and then pulling it back out and comparing that to a known good working bolt.

Usually just lubing the hell out of the bolt and inside the carrier and working it back and forth a bit will loosen it up enough that it'll work and it'll feel a lot better after you put a few rounds through it.

You can check headspace if you have the gauges but I doubt that's your problem.