Gas Ram

Gas ram air rifles are similar to spring-piston guns in that both types are cocked and shot the same way. But unlike a spring-piston gun, cocking a gasram rifle compresses a piston and compressed air in a tube (similar to the pneumatic rifles mentioned earlier). The tube is filled with compressed air, but cocking the rifle compresses the air even more. When the trigger is released, the piston is pushed forward and air is forced into the compression chamber. This powers the pellet down the barrel.

The great thing about gasram rifles is that they retain the air in the cylinder and last for years. Shots are smooth too because there’s no metal spring inside of the gun.