TexasCHLforum.com

It's really hard to compare calibers any more, with specialty companies making all kinds of ammunition. The standard, plain vanilla .45 ammo, for example, has about 350 ft. lbs. of energy with a muzzle velocity of about 830 fps. Buffalo Bore's 9mm +P+ has 500 ft. lbs. at 1400 fps., which approaches many .357 magnum loadings. Myself, I would MUCH rather have a 17 round magazine of the latter than a 6 round magazine of the former.

An excellent web site for your Bookmarks is at:

http://www.ballistics101.com/9mm.php

Use the drop down menus to change calibers. This page shows the energy/velocity of virtually every brand of ammo made. It's quite fascinating to study.