If you are handy, lightly polish the chamber.
I used a dowel rod in a drill. I used masking tape and tightly wrapped the end to closely match the chamber size (use a bullet as a model)
I then used a car polish on the tape and used the drill for 30 seconds to polish
it cleaned the same issue up on both my and my friends new AR
An imperfect servant of my Lord and Saviour, Jesus