I have a C3 lower that I got from Chris at SemperFi Arms a couple of years ago. After I got my winnings from the LaRue UHFO drawing I was going to use the C3 lower to put the LT upper on. When I tried to tighten the grip screw, it never would tighten down all the way. When  I took the screw back out, the Heli-coil backed out. It seems that the threads on the insert and the screw don't match. I tried several screws and none of them worked.  Luckily I had another lower to use.





Is C3 still in business or is there an easy fix for this?

 

I had the same issue with one of mine and posted it here, and someone notified Buzz at C3 Defense so that he contacted me (I'll PM you his username) and he was able to fix it in just a few minutes.

I emailed C3. Waiting for a response.