Saturday at the range, I had a box of Federal Premium Mag-Shok Turkey Loads: 12 gauge, 3", 2 oz, 4 shot. Dram Eq of 4. Muzzle Velocity of 1175 FPS. I shot these through my 870 Police. I did not hand over the shotgun afterwards to my girlfriend to shoot these loads because the recoil was very heavy.
We'd just shot some Winchester Light Target Loads: 7 1/2 shot, 1 1/8 oz, 2 3/4 Dr Eq and a few Brenneke 1 oz slugs with pleasure (I love those slugs). We breezed through the Target Loads and the one box of Brennekes I'd brought, but the Turkey Load was brutal in comparison. I shot three after the Brennekes and then to cap the evening at the range I shot three more.
What would this load's recoil compare to in a rifle cartridge? Or better yet, if someone can compare all three of these loads to a rifle I'd appreciate it. As I said, we were shooting a Remington 870 Police (4901). This is the wood stocked model with an 18" barrel. The buttpad is not the new R3 style, but what you see on the gun at this link.
Having shot all of them, and a few bolt action rifles besides, I'll take a stab at it:
The light loads are comparable to the felt recoil of a .243 or a .25-06...
The Brenneke slugs are comparable to that of a .308 or .30-06...
The Federal 3" turkey loads are comparable to the felt recoil of a 7mm Mag, but not quite as stout as a .300WM...
Now, those are just my opinions, and the recoil pulse is different between a rifle and a shotgun, but I think that might give you an idea..