how does it work?

like i can shoot 5 bullets but only 2-3 shotgun shells?
how do i work out what each gun costs to shoot in VATS?

(and also this will sound dumb but know how to jump on the xbox version?)

thanks

xbox jump is Y and it depends on the recoil used by the weapon i.e. strenght required to use it the less strength the more rounds you can shoot off more strength required like a shotgun you can only handle 2-3 at a time