the bit about it knocking an Indian war pony off it's feet at 100yds
Howdy
There is a big difference between incapacitating a horse at 100 yards, and "knocking it off its feet".
Clearly a pony is a bigger target than the man on its back. Now I don't know about anybody else, but at 100 yards I would have trouble hitting a target the size of a horse or a pony with a revolver, particularly if the animal was galloping.
I suppose if I took the time to sit down, brace my back against a tree, and held the revolver with both hands between my knees a la Elmer Keith I could do it. Maybe I would need a couple of shots to walk up to the target. Cavalrymen generally did not have an opportunity to do that. They would have been armed with a single shot Trapdoor carbine, probably firing the watered down version of the 45-70 cartridge with only 55 grains of Black Powder under a 405 grain bullet. Probably the only time they would have drawn their Colts is if a band of hostiles broke through a defensive line. At close range, with a well placed shot a 250 grain bullet propelled by 40 grains of Black Powder from a 7 1/2" barreled Colt would certainly have incapacitated a horse, if it was hit in the vitals. Knock it off its feet? Probably not.
If you have not fired a .45 Colt with a case full of black powder under a 250 grain lead bullet, you should.
I have done this a bazillion times. This is a photo of the recoil of a 45 Colt round fired from a 4 3/4" Colt. My standard load for 45 Colt is about 35 grains of FFg Schuetzen under a 250 grain bullet. The original 40 grain load is difficult to duplicate in modern brass without compressing the dickens out of the powder. Modern brass has less case capacity than the old copper cased, Benet primed, Frankford Arsenal 45 Colt rounds.
I think it was in the John Wayne movie, The Sons of Katie Elder where actor Jeremy Slate is shot as he is jumping in the air. The shot doesn't just knock him down, it knocks him completely backwards. Clearly, he was attached to a rope, and as the scene was shot, somebody yanked the rope to pull him backwards. Pure movie baloney. .308 Norma is correct. If my loads were powerful enough to knock a 1000 pound animal off its feet, the equal and opposite reaction would knock me off my feet and into the next county.
I shoot these rounds all the time. Recoil has not knocked be off my feet yet.