Here's a bit of insider trivia about "Serious" shotguns....
Back when the accessorizing craze was first gaining ground, everyone preached the virtues of a mag extension. What was widely known but NEVER talked about was that adding 7-10 oz of weight to a short bbled 870 was cutting the felt recoil 6-10%. Adding a few oz of weight to the stock for balance would drop the kick another 6% or so. When the Side Saddles came out, we all could see the possibilities, and feverishly added another 8 oz.
My HD 870 has it all, runs about 9 1/2 lbs in Ready status. What kick? Heh,heh.....
IOW, if fit and form are good, dropping the mass and speed of the load and/or adding weight to the weapon will take any of the remaining bite away.
However, if fit and form are bad, NOTHING will make a shotgun kick free unless it's taken to the limits, like a 410 size load in a 12 lb cannon.