Quote Originally Posted by Joelski View Post
Jerry, do you think a barrel with a properly installed extension would fix that problem? Sucks to throw good money after bad, and still have the LRBHO issue. It doesn't appear QC10 has an engineering solution of their own for either issue.
The NFA gunsmith was aware of the problem. While I don't know what they will do, I see several options open for the repair. a) Replace the barrel if the extension is bad [bad batch of barrels?] b) Install the existing barrel correctly if the upper receive is true [poor quality control on final assembly?] c) Use a milling machine to face the front of the upper receiver so the barrel will install perfectly square [bad batch of upper receivers?].

Since he knows the problem, it becomes obvious that these two are not the only occurrences. Everything covered under warranty, so money is no object

I have to believe they will fix the problem(s).