Olekman

I realize that it has been gone through several times by now - weapons won't accept different ammunition, unless the ammo itself is "ammo.rocket". My question is though, would it be possible to create another "subtype" of ammo? Something like "ammo.shotgun", that could later be worked out as "ammo.shotgun.slug", "ammo.shotgun.buck" etc. It seems as the only option, unless it's hardcoded.