About 3 weeks ago I shot (100 rounds) thru my 10.5" with the FA556k attached (via the MB556) and sat down to clean them today and can not for the life of me remove the can. using manual force.
I assume that some carbon fouled the joint, but don’t want to damage either the can or it’s host.
Yes, normal for Knight’s cans and I would imagine any other FH mounted suppressor.
Picture this, there is metal being heated and carbon buildup in recessed spaces at the same time once it cools back down and the metal contracts back to its room temp size it is gonna be snug.
Like has been suggested, next time you shoot it a few times to warm it back up it should come off, get the carbon off your FH and it should work as normal. You may want to make a note to self how many rounds it takes to make it “stick”.
The same thing happened to me on my 556K. I tried to shoot and remove it 3-5 shots at a time. I eventually had to shoot the damn thing off. That worked. Scratched the hell out of it, but a ruined oven mit and glove, and a scorched hand later, its off.
When you do get it off, take a stainless steel wire brush to the adapter and remove all of the carbon. Do the same for the area inside the suppressor that you can access. It will fit like new. The nylon one they supply is worthless for carbon
Good luck
ETA - if you can safely (without crushing it) put the supressor in a vice, loosen the retaing collar, and use the additional leverage provided by securing it in a vice and twisting / pulling the rifle. I’d be reasonable about the amount of twisting you do - you don’t want to damage your reciever. On second thought, it probably be safer to put the barrel in the vice and use your hands to rip that mutha off, don’t fall on your ass when it breaks loose.
Withdraw strider fixed blade knife from sheath in waist band. Smack end of silencer towards chamber 3-5 times while holding knife loosely in hand. UNtwist latch so silencer is unlocked. Smack rear end towards direction barrel is pointing.
Silencer will come off. It doesn’t take a lot of force. It might dick up your finish, but it won’t hurt the can. It’s a tool, not a trophy.
Next time make sure you take it off and clean it regularly. Fast attach mounts require removing the suppressor every so often and cleaning the interfaces. That’s why your suppressor came with a bottle brush looking guy.
If I was at the range next to you, I would have done it for you.