Insomniac wrote:So would that mean that two objects with the same momentum won't necessarily have the same amount of kinetic energy?
Two objects with equal momentum will ONLY have equal kinetic energy if they are of equal mass.
And as Jack has already begun to show, the lesser the mass for the same momentum, the higher the kinetic energy - and of course, vice versa. Which is why guns, at usually about two or three orders of magnitude more massive than their projectiles, don't simply tear the shooters arm off.
You need to find the most violently recoiling weapons for them to have a recoil energy that exceeds the muzzle energy even of a .22 Long Rifle.
More than 100 ft-lbf of recoil energy is very unusual (although .700 Nitro rifles can be as much as 200 ft-lbf, best described with the word "ouch".) and most people, were they presented with such a rifle, would probably drop it on firing. I'm sure you'll've seen the videos of people firing .577 T-Rex on Youtube.