It's the best part about the game seeing your enemies limbs heads fly off in slow motion :disco:
I can't stand that either.
A shotgun doesn't 'detach' your head :/
The clean "seams" only work for bladed weapons (and even then it's extreme. Lets see someone cleave through a femur with a cleaver... come on) - they should be more "torn" in any other case. Still, it would more likely burst the part (whole or in part) vs just detaching it.
Rolling heads are funny, but silly at the same time.