Nah! You can't use bullets to commit warp crimes because of the relativistic paradoxes to which allusion has already been made. Nor can you use a bow and arrow, a slingshot or a blowgun. And even if you could, just thinking about all those relativistic paradoxes would give you a headache and upset your constitution so severely you'd never be able to actually do the dirty deed.

Here is a brief list of weapons with which warp crimes can be committed with no violation of Dr. Einstein's basic tenets and no nausea induced by having to think too much:

Dental floss
A 3 foot length of 2"x4"
An epee
A dirk
A spading fork
A Calton or Anvil guitar case (Martin thermoplastic cases make lousy weapons.)
A fiddle bow
A brick (though only if used strictly as a bludgeon, not as a projectile)
The baldheaded end of a broom (Well, I suppose you could beat someone to death with the hairy end of a broom but it'd take eons. But, what the heck? What's a few eons between enemies when you're travelin' at FTL speeds and all your molecules are already spread out over 197 dimensions in 12 universes?)

I'll quit now. I feel a headache coming on.