FWIW, I bought the newest (at the time) factory NATO stock version NIB in early 2015, I don't have a log for the gun, but at least 1500+ rounds down range and never an issue wrt reliability, but I did find some types of polymer mags did not fit or lock in well. The bulk of my magazine stockpile are standard aluminum 30 round AR types, and it seems to get along fine with all of those and I quit trying the others.