I just received my new Armalite upper (ar15t).  When I tried to mate it to my Colt lower I found that she wouldn’t fit!  It seems that the handguard assembly is to close to the pivot ring.  Is there a way to bring the handguard locking ring forward an eighth of an inch?  If that can’t be done, my only other thought is to grind or file down the rings on the lower somewhat.  The upper seems to have been test fired, (there’s a little ding on the shell deflector) so I know that a lower was fitted to it at least once before.  Has anyone  ever had this problem?

Are you using an offset pin on that Colt lower?  

Before you go and modify it just sell it to me for $5.

Just kidding, call Armalite and see what they say.  As far as it being test fired, all manufactures test there weapons before they leave the factory.  This is to ensure there is no fatal flaw with some componenet (heat treating of materials, badly stressed metals, or bad barrels).  This especially true when the parts are made by a third party vendor.

I called Armalite. They didn't know what to think of it.  They said send both parts to us.  I'll do that if I can't get it done more easily.
BUD, What is an offset pin?  I'm using my original pin from my Colt.  It goes throgh each hole seperatly, but I can't get the two hole to mesh.