Found this stuff somewhere on the net a long time ago. According to the Shotgun Recoil Table the recoil energy of a 1 ounce target load at 1180 fps in a typical 7.5 pound gun is 17.3 ft. lbs., about like the recoil of a .270 rifle. The typical promotional shell with 1 ounce of shot at 1290 fps in the same shotgun hits back with around 20.8 ft. lbs. of recoil energy, about like an average .30-06 rifle. These loads deliver about as much recoil as most shooters can stand on a continuing basis. A typical high-brass load with 1 1/4 ounces of shot at a MV of 1330 fps fired in a 7.5 pound shotgun is much worse. It belts the shooter with 36.4 ft. lbs. of recoil. This is roughly equivalent to the kick of a .300 Ultra Mag. rifle. Average hunters should strictly limit the number of such loads they fire to avoid developing a flinch. 12 gauge Magnum shells are even worse. A 2 3/4 inch Magnum shell throwing 1 1/2 ounces of shot at 1260 fps from a 7.5 pound shotgun belts the shooter with 45.9 ft. lbs. of recoil, somewhat more than the recoil of a typical .375 H&H Magnum rifle shooting 300 grain factory loads! And the 3 inch Magnum 12 gauge shell firing 1 7/8 ounces of shot at a MV of 1210 fps in that same 7.5 pound shotgun slams the shooter with over 60 ft. lbs. of recoil energy. This is equivalent to the recoil of a .378 Weatherby Magnum rifle, and exceeds the recoil of a typical .458 Winchester Magnum rifle. This is literally recoil in the elephant gun class, and most shooters would be well advised to avoid such loads.