Allowing multiple ammo "categories" on one gun

[atlas1205]

So i'm making this weapon manufacturing mod and ran into a problem:
Since I've defined all the ammo with different "categories" according to their calibers, there's no way any vanilla guns can use them, because most weapons have their ammo_type defined with category = "bullet".

Would it be possible to force weapons that use "bullet" to accept my ammo as well?
I thought about

Code: Select all

category = {"bullet","556x45"}

but i doubt it will work...