You're going to be amazed...
Shot two 870's with SpecOps on them.
A 12ga and 20ga.
The recoil on the 20 is cut about in half.
With Magnum slugs the 12 has the same recoil as the 20 does with standard slugs, Same for buckshot. By that I mean it has the same recoil as the 20ga with the SpecOps installed, which is the same as saying "not much".
With reduced recoil 00 Buck, the 12ga doesnt even feel like a shotgun. It felt like firing a blank. I havent shot a .410 in a long time, but that is what came to mind. (I should say that I was but a young lad of a mere 115lbs the last time I shot a .410)
When firing the shotgun, try placing stock against your shoulder and focus on holding the pistol grip still. The SG recoils and moves over top of the pistol grip. That makes a difference in felt recoil over tightly pulling the SG in against shoulder. Doing it that way, I could hardly feel the recoil on my shoulder.