Check out this shot-shell recoil chart out on Chuck Hawks excellent firearms web site:
You'll see that load at the bottom of the chart, or the harshest recoil there is - around 60 ft. lbs.!!! :shock:
That is fully three times the force I feel when shooting my favorite target loads - I can't Imagine... Man, that load would knock me over even if it was "in the pocket"!
P.S. - An excerpt from another excellent article that Chuck Hawks writes describing 12 gauge magnum loads -
"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."
Read the article entirely here: