There are no general equipment dice. There are ammo dice, for guns only. Most automatic weapons have a ROF of up to 3 or 4, most semi-autos 1 or 2.
So for the majority of rolls you're rolling 2 dice (or 1, if unskilled). For most shooting, I'd say 4 or 5 dice is typical, but that's situational and depends a lot on your players as well.