strip the stock from the action, take out the gas plug, and undo the collar- then swing the cylinder out of the way off to the right or left- you may not have to take the stock off to do it- the flash hider NEED NOT come off - the collar is what holds the gas cylinder in place- once that's loose, you can swing the assembly off to the right or left to clear the lug- i'm talking about everything from the stock forward to the front sight- just behind the gas plug is the threaded collar- undo that, and the whole assembly pushes forward, then you can swing it right or left