My son and I shoot trap occasionally. We want to know if there is any difference between shooting our 20ga full choke with 7 1/2 shot, 7/8 oz. loads , verses our 12 ga with 7/8 oz loads same shot. When both guns have 30″ bbls. ? We are not competitive shooters. Just having fun .
The general rule of thumb is that, for a given load of shot, the larger the shotgun bore the better. This is because the larger bore results in the load having a shorter column height. In turn, that makes for less distorted shot due to setback on ignition. That’s where the shot at the front of the column squashes the shot at the rear of the column when the powder goes off. The longer the column, the more squashing. The bottom line is that the larger bore will produce more round pellets than the smaller bore. This means better and more consistent patterns.
Dem’s da facts. But, what I don’t know is just how much difference there really is. The 12 gauge 7/8 oz load will be better, but will it be better enough to matter in the slightest? Dunno. My guess is that it might actually matter for one or two birds out of 100, but that’s just a guess. I don’t think it’s a big deal. Certainly it shouldn’t matter for someone who is just shooting trap for fun.
Remember the old Technoid dictum: When you shoot to win, you often lose. When you shoot for fun, you always win.
Shotgun Report’s Technoid