When Pygmy came out like ole' 20ga it carried 3/4oz shot. This was not good because cartridge pressure was too low therefore 7/8oz charge of shot was used which is modern 20ga load. When compared to the 2&1/2" 12ga the 2" version achieves similar velocity at lower pressures which in practical terms is meaningless.
The winner is short barreled open choked category would be Bernardelli 2&3/4" game gun. Why? Because one can use 2", 2.5" and 2&3/4" shells and if non-tox shot is needed on the hunting trip local Walmart will have Winchester Expert steel at about $8-$9/box. No old vintage gun can be so versatile.
The 16ga doesn't even enter the game.