RE: Effective range of 12 ga. 3 and 1/2" loads
Welcome to the forums.
107 yards is a joke. I couldn't hit a turkey witha deer slug that far. As far as range, I use a Rem 870 Supermag with 3 1/2 Win HV #5's, and I won't shoot past 50 yards. My pattern opens up far too much beyond that, I don't like to shoot past 40, but 50 is my absolute limit. I have patterned my gun several times with different shells and tubes, and none did well past 50.