I am contemplating the purchase of a .577. Since this is a black powder rifle I understand that the cordite load is 90 grains pushing a 650 grain bullet at 1950 ft. per second. This is suppose to generate 5500 ft. pounds of energy. The gun weighs 11 lb. 10 oz. The Recoil Calculator states that this should generate 66 ft. pounds of recoil. The heaviest rifle (in terms of recoil) that I have shot to date is a Ruger #1 Tropical in .458 with a 510 grain bullet (factory load). I did not find this offensive. Could it be compaired to a shot gun with slugs? I realize that everyones tolerance for recoil is different but I would be interested in your opinions.