Abstract: Disclosed is an ultra-low dose injection delivery system. The system includes a pistol grip having front and rear handles, a barrel containing an injectable fluid, and a bottle mount integrated with the barrel for receiving and securing a bottle holder, the bottle mount including a conduit running from a spike tip that punctures a bung of the bottle into the barrel. The system further includes a needle coupling attached to the barrel adapted to receive and secure a needle and a plunger for assisting in drawing an injectable fluid from a bottle into the barrel and for forcing the injectable fluid out of the barrel. A ratcheting mechanism incrementally advances a selectable ultra-low dose of injectable fluid out of the barrel upon a full stroke of the pistol grip. A full stroke is defined as advancing the plunger forward by squeezing the front and rear handles together until the ratcheting mechanism stops the plunger from further advancing yet still allows the front and rear handles to be fully squeezed.