View Full Version : AR-15 locking key problems

November 6, 2009, 05:23 PM
Okay, just finished building my first AR and can't, for the life of me, figure how this "locking key" works.

I installed the magpul ASAP and can't finalize this step. Any help is greatly appreciated.

November 6, 2009, 05:47 PM
I am not sure what you are refering to, maybe the wrench that tightens the castle nut up? The only key on the rifle is on top of the BCG and I know that is not what you are talking about.

November 6, 2009, 05:52 PM
I can hand tighten the receiver extension just fine, when I install this "locking key" (or try to install) I can't line up the lines right and the extension can't be tightened correctly?

November 6, 2009, 05:57 PM
Ok, you got be talking about the castle nut http://www.bravocompanyusa.com/SearchResults.asp?Search=castle+nut right?

And you can't get this http://www.bravocompanyusa.com/Daniel-Defense-AR15-Lite-Wrench-p/dd%20ar15-lite%20wrench.htm kind of wrench lined up correctly?

November 6, 2009, 06:00 PM
yes, nice use of the pictures - sorry about the lingo, it is the castle nut - hope that helps clear up my question.

November 6, 2009, 06:03 PM
Try this, this is the only thing I can think you might be doing. Take the wrench and put it over the tube and then slide it up on to the nut rather than coming on top the nut itself and trying to line it up, it won't go on that way. Slide it into place by holding over the extension tube.