One of the greatest revolutions in spring powered air rifle technology was the development the gas spring, or gas ram piston. This is a technology that replaces the traditional coil spring that resides in the receiver of an air rifle with a gas "spring". The end result is a slght gain in power when compared to a similar spring but most notably, a much smoother cocking stroke and less vibration during the shot. Power, ease of use, and better accuracy are three great reasons to look for a gas piston power plant for your next airgun purchase. Our T.N.T Gas Piston and ReAxis Gas Piston air rifles set that standard for gas piston air rifle performance.