Abstract: In a paintball gun 10 the valve member 17 which controls communication between the gas canister 13 and the barrel 11 of the gun is balanced by a piston 23. When the chamber 21 is pressurized the piston 23 helps to unseat the valve member 17 when the latter is struck by a hammer 15, thus reducing recoil and permitting use of lighter, less robust materials.

Abstract: In a paintball gun mechanism compressed air is admitted through passages (16) to the interior of the barrel (10) where it will move forward a hollow bolt (11) until it can escape through the bolt (11) to fire a paintball. The bolt (11) is then moved backward by compressed air in a chamber (15) until a central formation (12) of the bolt (11) enters a guide (13) to close a firing chamber (14) behind the bolt (11). The invention provides a valve member (17) independent of the bolt (11) which is biased by a spring (18) to close off the firing chamber (14) from the passages (16) except when displaced by the formation (12) of the bolt (11) during a final part of the rearward movement of the bolt (11).

Abstract: A gas pressure regulator of the kind in which a valve member is spring biased to the valve-open position and is moved to the valve-closed position when upstream pressure at an outlet overcomes the spring is arranged such that gas pressure at an inlet end of the valve member 12 does not influence it in the valve-opening direction. In the embodiment of FIGS. 3 and 4 a bottom end of the valve member receives a piston-like plug. Openings in the wall of the valve member are occluded when the valve is closed. In the open position of the valve member pressure is equal all round each opening. In another embodiment of the invention a spool is provided having one enlarged end within the valve member and another outside it. Pressure on the combined surfaces of the end and the end of the valve member is equal to the pressure on the end of the spool.

Abstract: A paintball gun assembly comprises a casing having a barrel and a bolt moveable in the barrel to select and fire paintballs. There are located in the casing under the barrel in a linear array generally parallel with the barrel a low pressure regulator, a chamber for air under pressure, a spool valve, a poppet valve, a solenoid and a battery. The spool valve comprises an elongated housing of circular section in which a spool is reciprocable to move seals on the spool relative to radial openings of the housing. The valve has an input opening at one end of the spool and the spool has a longitudinal bore to communicate said input opening with the periphery of the spool at a position between an adjacent pair of said seals.

Abstract: A valve for communicating a source 14 of compressed fluid with an opening 13 of an adjacent chamber 12 in a sleeve 11 comprises a circumferentially separated array of depressions 15 in the outer periphery of a bolt 10. Areas 19 and 20 of the bolt periphery between the depressions 15 serve to support the radially inner side of an O-ring seal 16 when the latter is aligned with the depressions.

Abstract: In a paintball gun (10) the valve member (17) which controls communication between the gas canister (13) and the barrel (11) of the gun is balanced by a piston (23). When the chamber (21) is pressurised. the piston (23) helps to unseat the valve member (17) when the latter is struck by a hammer (15), thus reducing recoil and permitting use of lighter, less robust materials.