Kutter/Jim Yes the part in the photo is the one I am trying to use; the magazine tube guide (for lack of a better term) prevents it from turning more than 1/2 turn--as it is now. It seems like part of the rib would have to be removed then reinstalled later(after the barrel ext. is on) for it to make it all the way around--however many turns it would need. Am I looking at it correctly?

[IMG]