I have a quick compatibility question about barrels. Lets say i have an M4 with an M4 length barrel, but down-grade in size so much the barrel becomes too long, would getting an MP5 length barrel work in the gun, or would i need an something meant for M4 barrels like the CQBR barrel?
Same goes with extendeing it. Lets say its an M16. Can i get a PSG1 barrel or do i need say a M16 plus barrel?