Abstract: A compressed air rifle comprising a cylinder containing a freely slidable piston that divides the interior of the cylinder into a rear chamber adapted to be charged with a compressed gas and a forward chamber defining an air compression chamber, a unidirectional valve for charging the rear chamber with compressed gas, a member mounted on the forward end of the cylinder having a rifle barrel guide and a projectile insertion opening, an open-ended rifle barrel coaxial with said cylinder slidably mounted in the guide for movement between a first loading position wherein it may receive in its forward open end a projectile inserted through the insertion opening, a second position wherein it has been thrust into said cylinder sufficiently to push the piston into locking engagement with a trigger controlled latch, and a third firing position wherein it closes the insertion opening and its rear open end is substantially at the forward end of the compression chamber whereby when said trigger is actuated to release the