Patent ID: 7036496

Claim:
A compressed-gas gun-firing mechanism which comprises a barrel having a distal portion and a proximal portion: a cylindrical bolt in said proximal portion, said bolt having a given outer radius and a gas discharge channel extending from a radial intake port in a proximal section of the bolt to an axial discharge port at a distal end of the bolt; said channel defining an axial zone and an elbow between said intake port and said axial zone; whereby when said bolt is axially translated by a trigger mechanism said intake port lines up with a gas delivery port in the proximal portion of the barrel allowing compressed gas to enter said channel and apply recoiling pressure against said elbow, while, at the same time, applying firing pressure to a projectile located in said distal portion of the gum barrel; and, a sleeve slidingly inserted between said bolt and barrel and having a leading portion and a trailing portion; said sleeve further having a radial aperture in said trailing portion; resiliently compressible means between said bolt and said sleeve for biasing said leading portion ahead of said bolt and for keeping said intake port in line with said aperture; said barrel further having a radial projectile-admitting first port in said distal portion and a radial gas-admitting second port in said proximal portion; and means for translating said bolt and sleeve from a recoiled position wherein said leading portion obstructs said gas delivery port, to a firing position wherein said gas delivery port, aperture, and intake port are aligned up to allow expansion of gas through said channel and into said barrel; whereby a projectile partially inserted into said distal portion of the barrel causes said sleeve to resiliently slide over said barrel and said leading portion to close said intake port, thus preventing expansion of gas into said bolt and barrel.