No offence, but that's a load of BUNK!
bullets are NOT arrows, they mushroom while arrows cut. apples to bolling balls!
To relay numbers from ACTUAL TESTS (Bowhunter Dec/Jan 1999)
Ethafoam
Arrow #1 400gn 244.88 fps KE 53.28 penetration 12 1/32"
Arrow #2 600gn 200.88 fps KE 53.78 Penetration 11 15/16
Styrofoam (same arrows as ethafoam test)
Arrow #1 13 3/16"
Arrow #2 13 1/16"
These tests while not on actual animals, tests ONLY the differance in penetration through controled substances
NOTE: The lighter/ faster arrow had LESS KE, and MUCH less momentum...yet penetrated BETTER!!!
While a slender broadhead (Steelforce) should cut hide better than a stubby blade (Slick trick) It is the stubby head that penetrates BONE better (less surface area...works EVERY time in my tests). I don't think many worry about ANY head penetrating hide...but bone is another matter.
Of those 2 heads, both are 4 blade heads, and the slick trick has a LARGER cutting diameter! (should do even WORSE, but it does NOT)
Momentum, is NOT as good at estimating penetration as KE...and even KE has flaws..but is much closer than momentum.
HERE WE SEE ARROW #1 HAS .437 SLUG/FPS AND #2 HAS .5357 SLUG/FPS MOMENTUM.
LESS momentum penetrated as well or BETTER than MORE momentum! But the KE was nearly identical!
Again, NO offence, but I will take real data (even slightly NON scientific tests) OVER bullets vs. arrows ANY day of the week.