I do not believe the 10.5" is the correct length barrel for an XM-177 clone. Also, with the 10.5" barrel you can't use an XM-177 flash hider to obtain a 16" overall barrel length. The XM-177 flash hider is 5.5" so the correct length would need to be 11.5". Also, 11.5" does not require a gas port size change where the 10.5 may or may not. As for the bird cage flash hider not having the umpf to create enough allow the gas system to work correctly I don't see any issues with using one. That is what mine has. The way mine is set up it functions flawlessly with a standard run of the mill Colt SP1 bolt. My Commando's issues are because of a malfunctioning bolt not a gas port size. If it were then it would not run any better no matter what bolt it had in it.