[mbynack]

22 Mag has more than twice the energy of the .22LR and about the same as a .45 auto.

"The standard 40 grain bullet is now advertised to have a muzzle velocity of 1,910 fps in a 22" rifle barrel and carries 324 ft. lbs. of energy. From the 6.5" barrel of a revolver the velocity is 1400 fps with an energy of 174 ft. lbs"

45 ACP out of a six inch barrel has about 495 ft/lbs of energy.

Comparing both in a handgun, the 45 has almost three times the muzzle energy.

[yarddog]

I don't know where you are getting your .45 ACP but mine runs around 340 ft. lbs.

I once read a test of .45 ammo out of a Thompson carbine and it was only slightly more powerful than from a pistol.