A pneumatic assembly for a compressed gas gun having a hammer chamber including a hammer conduit, and a hammer with an aperture surrounding at least a portion of the hammer conduit. A compressed gas gun has a breech, a bolt moveable within the breech from a loading position to a firing position, a pneumatic assembly in communication with the breech, the pneumatic assembly comprising a high pressure chamber, and a hammer chamber. A discharge valve is disposed in the pneumatic assembly between the high pressure chamber and hammer chamber. A solenoid valve is provided for selectively supplying compressed gas to the hammer conduit.