The Spring-Piston mechanism is a projection method. Unlike Pre-Charged Pneumatic (PCP) Airguns, the Spring-Piston mechanism is similar to a car engine in that it uses springs under compression to move a piston which compresses an air cylinder.

The basic concept is that, a sudden spring-powered released of air, plunged against a pellet using the piston head as a seal, will force the pellet to accelerate down the barrel.