A linear bolt mechanism for a gun is provided, wherein a bolt moves between a firing position and an open position through linear motion, without requiring rotation of the bolt. The bolt includes a seating socket which engages a locking pin to permit travel of the bolt upon disposing the locking pin in a traveling position. The seating socket also engages the locking pin when the locking pin engages the locking socket, thereby precluding movement of the bolt with the locking pin in the locking position.