Hi there, My eldest daughter loves my M40-A1 but does not like the recoil. So this weekend she bought an 2004 M9 at the local gun show. We took it home and I showed her how to clean and lube it. We fired it at the range today. She loves it, but with all three mags. the slide would not lock open after the last round had been fired. The trigger safety does not reset 75-80% of the time when dry firing it, but it worked fine with live ammo. Also her first shot today we got a light primer hit. We were shooting UMC factory ammo, 115 grain, jacketed round nose. Ideas?