Firearms are interesting from a combat POV. It's pretty difficult to aim and fire if someone is gripping your hand, gaining control of the weapon is what I was taught in martial arts, though I never got to black belt. But the further you are from the target the better your chances of a clean shot, though beyond point blank range, aiming becomes more important.
So if someone is 1ft away and aware you are trying to shoot them, I would have no problem applying a penalty compared to say being 7ft away.