Todays 20ga shotguns with todays high performance 20ga sabot slugs can out shoot a 12ga. and it will take down deer size game just as quickly as the 12ga. I have alot of slug guns in both 20ga & 12ga, I best one is the Savage 220f 20ga., get yourself a quality 20ga., (doesn't matter on the action) that you really like with a rifled/cantilever barrel with quality sabots and you can kill deer size game out to 200yards once you get good with it