Abstract: A pneumatic spear gun has a stock supporting a barrel. The gun uses compressed gas to power a spear having movable vanes that slide along the shaft to become fixed at the base of the spear to rotate the spear and stabilize trajectory. The compressed gas is stored in a high pressure tank in the forearm of the gun. The tank also has a breathing regulator and mouthpiece. There is a gas handling system between the tank and the barrel for providing multiple single shots and regulating the flow of expanding gases.

Abstract: A pneumatic spear gun has a stock supporting a barrel. The gun uses compressed gas to power a spear having movable vanes that slide along the shaft to become fixed at the base of the spear to rotate the spear and stabilize trajectory. The compressed gas is stored in a high pressure tank in the fore arm of the gun. The tank also has a breathing regulator and mouthpiece. There is a gas handling system between the tank and the barrel for providing multiple single shots and regulating the flow of expanding gases.