idea started from here:
Prerequisites: Ballistic Skill 40, [Quick Draw, Rapid Reload for weapons with single shot and reload of 1/2]
Arbitrator (Arbitrator rank 5), Assassin (Secluse rank 4), Guardsman (Veteran rank 5), Scum (Renegade rank 4)
Cost 200
You have trained yourself to quickly put 2 rounds into the same target. With any weapon in single shot mode only, you can snap off an extra shot at the same target, at a -10 to the second shot. It is restricted to weapons that have a Reload of Free (after adjustment for Rapid Reload) or Thrown Weapons you can quickly draw or have more rounds in the magazine.
Rapid Fire
Prerequisites: Ballistic Skill 40, Basic Weapon Training (Primitive) or Thrown Weapon Training, Double Tap, Quick Draw, Rapid Reload
Cost 300
Assassin (Death Adept rank 6A or Moritat Reaper 6C) , Guardsman (Assault Veteran rank 6A or Marksman rank 7A), Scum (Stubjack rank 7A)
With much practice you are able to get off way more Primitive shots then it seems possible. Your rate of fire will become 1/2/equal to your AB with the ability to select the # shots you actually release. All targets need to be within a 45 degree arc. You do not get either Semi or Full Auto bonus to hit, but need to roll for each shot, and after 1/2 your AB round up take -10 to remaining shots. Rapid Fire is restricted to weapons that have a Reload of Free (after adjustment for Rapid Reload) or Thrown Weapons you can quickly draw.