Bought a 16in BCA upper in 7.62x39 upper. The first trip to the range was not fun at all. Cases stuck in the chamber, leaving the last round in the magazine . I took it apart and pollished the chamber. Changed from the Silver Bear soft points that are zinc plated to Wolf lacquer coated. Still had FTF and not loading last round from the ASC mags. Bought new mags from Midway. Stoner mags are probably ASC that is what the follower is marked. Put a 308 Armalite spring and H3 buffer in. Runs like a top with the Wolf now. Haven't tried the Silver Bear yet. Now that it runs I'll see how it groups when I have time.