On a trip last year, we were shoot 12 ga two shotguns with the same ammo. One of the shotguns fired all the rounds, the other shotgun (Mossberg 500) misfired several rounds on and off, e.g. load 5 and 3 misfire. For the misfires, the he rounds had an indication that the primer was struck. After searching online, if seems the shotgun had light primer strikes. I've had this shotgun for 6 years, and fire approx 20 rounds through it per year. Since it's a defender, it would be nice for it to have the ability to actually defend. Has anyone ever experienced this with a shotgun and been able to correct it? Can't determine if this is a fixable issue (something I can fix, something a gunsmith should fix, or if I should just buy another shotgun).