Well, a 4 bore rifle spits about think.
Makes a 454 look like a popgun
Looks like the 24lb 4 bore rifle sooting the 1/4 lb slug at 1400 ft/sec has a recoil E of ~200 ft-lbs(if the(400 grn) black powder gas v is 3600ft/sec). That will put most skidding backwards on their ass. A weatherby MArk V 460mag(10 lbs/open sight)has a recoil of 61 ft-lbs for a 7600 ft-lb E 500 grn slug at 2650ft/sec. Same as the Cassil here.