A paintball gun is sized and designed to appear like and operate in a manner similar to a conventional handgun. A removable magazine stores projectiles and propellant. The entire magazine is small enough to fit into a handle of a pistol. The magazine may be integrated with propellant and projectile portions locked together or separable. Standard carbon dioxide cartridges fit within the magazine. Paintballs may be staggered to increase the maximum magazine load. A user may selectively release just the projectile portion of the magazine, in order to leave the propellant undisturbed until fully expended. The magazine can be completely removed without substantial loss of propellant.

A pneumatic assembly for a paintball gun preferably includes a bolt slidable between an open and a closed position. The bolt preferably operates as a firing valve by permitting compressed gas to flow through the bolt when the bolt is in the closed position but preventing the transfer of compressed gas through the bolt when in the open position. This can be accomplished, for instance, by arranging a sealing member in communication with a surface of the bolt. A port is also arranged through a lateral sidewall of the bolt at a predetermined location. The bolt preferably slides in relation to the sealing member such that when the bolt is in an open position, the sealing member prevents compressed gas from flowing into the bolt, but when the bolt is in a closed position, compressed gas is permitted to flow into the bolt. Movement of the bolt is preferably controlled using a control valve such as an electronic solenoid valve.

A bolt assembly for a paintball gun preferably includes a valve stem having an output port that can supply compressed gas to a compressed gas storage chamber. A bolt is preferably slidably mounted on the valve stem to move between a forward and a rearward position. The bolt can include one or more bolt ports configured to communicate compressed gas from the compressed gas storage chamber to a forward end of the bolt for launching a paintball when the bolt is in the forward position. When the bolt is in a rearward position, the bolt ports preferably communicate compressed gas from the outlet port of the valve stem into the compressed gas storage chamber. A sealing member can be arranged on the valve stem in communication with the bolt to prevent compressed gas in the compressed gas storage chamber from entering a forward bolt chamber when the bolt is in the rearward position and to permit compressed gas to enter the forward bolt chamber through the bolt ports when the bolt is in the forward position. A flow control member is preferably slidably arranged on the valve stem and configured to permit a flow of compressed gas from the valve stem output port into the compressed gas storage chamber when the flow control member is in a first position and to restrict or prevent the flow of compressed gas from the valve stem output port into the compressed gas storage chamber when the flow control member is in a second position.