Not sure why, but I either have 10 yard shots or 40 yards. I hit a tom with #6 some years back at 40 yards, rolled him, he got up and vanished into may apples. I went to 4's because of this and haven't missed since. I'll stick with 4's unless I start missing.
I use a 12G, 3inch mag. Remington 1100 semiauto