I would call that with a brawl check that if you rolled enough success to disarm, that you could , with a few more advantage remove the power pack from the weapon meaning that its more difficult for the opponent to get the weapon up and running again. If they have a back up and quickdraw, it pushes them to use their secondary weapon, if they have no weapon , then they are on your territory and fighting you unarmed. This is something that a ranged combatant cannot do to a brawler and a melee weapon doesn't run out of ammo. The trade off is that it is possible for the ranged combatant to delay people getting into close range, things like called shots to the legs etc, however this means that it becomes more than just throwing shots at each other across the room.