So I shoot a mag of 150 gr FMJ .300 Blackout thru my new S&W M&P in .300 Whisper - no prob Bob. I then mount the newly acquired AAC 762-SDN-6 and load a mag of Hornady 208 gr .300 Whisper subsonic factory ammo and blast 10-12 rounds, I then hand the rifle to another shooter who shoots 7-8 rounds when the bolt jams in the fully rearward position. I then find the remaining ammo is dusted with carbon. I cannot get the bolt to move. I pull the mag and suppressor. Copper chips fall out of the suppressor and there are chips/shavings crammed into the slots of the flash hider. I contacted AAC, they were very helpful, and determined that there was not a baffle strike. They think a bullet shed it's jacket in the blast chamber. When I raised the muzzle I dumped said shavings into the rifle action which has made it even harder to get the bolt to move. I "stabbed" the muzzle into a pad on the floor and freed the bolt. I cleaned out the shavings and the bolt is free again. The rifle, flash hider, and suppressor all seem fine. I am going to tear down the rifle and give it a thorough cleaning and check it over. I am going to shoot the rifle with out the suppressor and put the muzzle in a box and see if a can "catch" any shavings if the same thing happens and see if the bullet is stable when it exits the far side. Has anyone had this happen to them or heard of it? BTW - shooting suppressed is AWESOME!!!! Only hear the rifle cycle but you can hear the bullet impact which is huge when blasting old TVs, bowling pins, railroad ties, etc. You never hear the target sounds when unsuppressed. Too cool!