Got a 10.5" 450 Bushmaster upper from Bear Creek (I know I know) with dreams of shooting piggy pigs. I have two lancer 20rd battle mags and tromix followers, 2 20rd SS mags, one SS 30rd mag and one lancer 10rd battle mag (notched the front of this mag) put chambers tactical single stack followers in the latter four mags. Shooting Hornady 250gr FTX factory loads. Same issue with all the mags. Bolt won't seat 50% of the time on follow up rounds. Cases look pretty boogered up, gaulded on some of them, had to snatch on it pretty hard to get a fresh round out of the chamber that wouldnt fire. Trigger snapped but it did not fully strike the primer, it is the last casing pic. Here are a few pics. First pic is of two rounds put into a mag and cycled by hand. The rest are empty casings cycled by the gun.