I don't know if this is the proper forum, so if not, please move to where it should be.
With all things being equal for both gauges, shot size, choke, velocity, etc,. are the 20 gauge 7/8 ounce, 1 ounce and 1 1/8 ounce loads equal in performance to a 12 gauge? I am referring strictly to the performance of the ammunition and totally disregarding the gun, with respect to handling, recoil and so forth.