BCG issue

Does The brass fit in the bolt normally when out of the gun.

Try lubing up the new one. I have had that happen with new dry bcg's if I don't oil them up first. Once they break in the stickiness goes away, usually by the end of the first mag.

I also had a PSA BCG that did not function properly. It was bored slightly undersized and would bind on the bolt. It would fire and extract and close but caused very poor accuracy. I though a couple hundred rounds would break it in but that did not happen. I replaced it with a BCM BCG and have no more problems. While most people have good luck with PSA I am the unlucky guy that has had several parts out of spec.

Could the cam pin be out of spec?

Likely tight gas rings, put couple drops of oil on the rings and bolt. Will loosen up with use. I had a PSA 7.62x39 did that, I used a heavy recoil spring when it was new. Wore in after a while. Also check extractor tension, if too stiff, remove the extractor O ring helps.

AR bolts like to run wet. Lube it up. Another suggestion, with the AR completely assembled (and no ammo around) pull the charging handle all the way back and let go. Cycle the bolt like that 100 times then go get some good ammo (I prefer mil surplus 5.56) and shoot at least 4 30 round magazines through the gun.

That is my procedure for every AR I build.

+1 on extractor tension. I have helped bolt function by carefully polishing the extractor face to help it slip over the cartridge rim.