How about putting a spell rune, fireball, on each bullet (requires use of an arcane list found originally in RMCI and currently in Arcane Companion)?
Now imagine a Black Numenorean wearing a ring of might and weilding two heavy machine guns with ammo so prepared. Remember, the ring of might raises level bonus up to +5/lvl and allows use of highest OB for all attacks.
Guns can be so much fun.