Wouldn't this also apply to primary fire mode? After all, you *did* pull that pin out, so when your lifeless hand hits the ground, it should release the hand grenade and the clip should pop out starting the 4 second fuse.
Serp did this, and I thought it did hand grenade pretty well. Sure, the range on that shrapnel seemed a little bogus at times, and maybe the damage was a little excessive. Still, it was damn cool being able to *see* the jagged spikes of metal flying thru the air at high speeds and richoceting off of walls with sparks flying just before it takes your head off.