ORIGINAL: quiksilver

Another list offactors that seem to have been ignored here is the frontal surface area of the projectile at point of impact, the broadhead's performance through bony, cartilagenous materials, arrow diameter, shaft drag through the viscous materials inside the body cavity, etc....

In sum, KE and Momentum are nice benchmarks for penetration potential, but it definitely doesn't end there.

To put it in its simplest terms, I'll demonstrate with a game of dodgeball. If I picked up a standard NCAA basketball (21 oz. = 9187 Grains), and threw it at your headat 40 Miles per Hour (59 Feet Per Second), you would have 71 pounds of Kinetic Energy hurtling at your dome, ready to slap you silly.

Now, if the ball would slam you in the earhole, it might knock your toupee off, but it surely won't decapitate you, orgouge a deep divotinto the side ofyour skull.

Now, compare that to a game of dodgeball where we're using a 400 grain arrow, traveling at 280 FPS tipped with a chisel-tip broadhead. Again, the same 71 foot pounds of kinetic energy - this time with the forceonly focused over a much, much smaller area. This game of dodgeball will certainly end badly if you're on the business end of that arrow.

KE and momentum are both worthless without considering these intangibles:cutting diameters, arrow diameters, fluid/bony penetration, broadhead structural integrity at high speed impact, etc...