US Patent 7870852 Pneumatically powered projectile launching device

The pneumatically powered projectile launching device has a bolt located within a body. A front gas chamber in the body has an opening through which the bolt extends into the chamber. The bolt can move forward and backward thereby changing the volume of the front chamber. The bolt has a backward facing working surface. A gas valve in the body selectively releases compressed gas into the chamber. The released gas applies pressure on the backward facing working surface of the bolt to move the bolt forward, and then passes through a passage in the bolt to pneumatically force the projectile to leave the device. Other embodiments are also described and claimed.