A linear magazine for an air gun advances upon actuation of a cocking mechanism. The magazine carries multiple projectiles for the air gun and translates perpendicularly to the bore (i.e., barrel) of the air gun to advance to the next projectile. The magazine places a series of projectiles in line with the bore of the gun while serving as a chamber for the projectile and gun and sealing to the air orifice and barrel bore of the air gun. In one embodiment, each hole or chamber of the linear magazine is arranged in a single row.