300BlkTalk

New upper, normally run a BLK rifle, but switched to pistol after giving the rifle to son. Run wet, hand cycled it about 25 times, at first it was doing this basically every shot. Towards the bottom of the second mag, I could shoot 2 or 3 before it would jam with the fired case and the new cartridge both crammed into the mouth of the chamber.

This is a new one on me.

https://ibb.co/D4W9qnH

What are you running for ammo?

I don't have a huge amount of experience with the BLK, but when I was running butterfly fart loads in my PCC I would get that malfunction. I assumed at the time that the bolt wasn't going back far enough to get rid of the spent case, but going back far enough to clear the next cartridge. My PCC is a blowback, but maybe the problem is similar? Not enough oomph? But in your gas gun it might be not enough gas? I had something quite similar in a gas gun with an adjustable gas block. My solution was to close the bleed to atmosphere a bit and send more gas to the piston.

edit: you might try single loading one round in a magazine and firing it. Do it a bunch of times unless you see the malfunction right away. Look for anything in the BCG path that might be screwing it up, or maybe more gas.

I once had problems with a .22 and it was due to the plastic mag lips interfering with the movement of the slide.

Please let us know how you make out.