Double Naught Spy
Sus Venator
Shotguns tend to weigh less and have worse ergonomics shooting heavy loads.
Off a bench, the shotgun will clear your sinuses. They can be brutal to sight in with slugs.
I saw a buddy of mine break a bone in his cheek sighting in a 12 ga with slugs off the bench.
For short range shooting, inside 75 yards, the 12 ga. slug is superior in many ways. Regardless of distance, recoil is not a way in which the 12 ga. is superior. I enjoy shooting my .45-70, even off the bench.
For comparison. I can get through 3-5 slugs off the bench before my time with the 12 ga is done, but I have put over 100 down range from the shoulder before lunch time and not been in as much pain that day or the following day than with shooting off the bench.
With a .45-70, 40 rounds off the bench is about it for me and the only thing limiting shoulder firing is finances.
I like hunting with my .45-70. I get less and better controlled recoil from a lighter gun than my 12 ga shotgun.
Oh, my guns are a Marlin 1995 at about 7.5 lbs. and a Rem 870 at a bit over 8 lbs with a light and sidesaddle.