Back in the day I taught Marines bound for embassy duty.
We were shooting S&W M19. Three common stoppages,
1 - broken hammer nose (firing pin). No immediate action for that...other than having a backup. It was an easy fix for the range armorer though.
2 - cylinder lockup from ejector rod backing out. Just need to check in often.
3 - cylinder lockup from unburned powder under ejector star, preventing full seating of the star. A by product of doing combat reloads with ammo that doesn't burn clean.
