With an adjustable gas block you shouldn't have to turn it into a bolt gun for suppressed, just adjust the gas block until you get the least amount of gas needed to cycle the BCG when suppressed. When I switched all of my DI guns over to suppressed setups I put an adjustable gas block and the quick mount muzzle device on them. I then took them out and put one round in the mag and loaded it up. Fired it if the BCG locked back I turned the gas down and did it again until it did not lock back. Once I got to that point I turned the gas up one notch made sure I got the BCG to lock back and called it good. took me about 4 shots if I remember correctly. I don't remember getting any blowback in my face while doing this testing. I also am running just regular charging handles in my uppers so no special gasbuster handles for me.
I should have some free time soon so I will go shoot the guns supressed and see if I notice any gas blowback on them and will let you know.
