A review on the physiology of Insulin like Growth Factor-I (IGF-I) ... by Debnath, Surajit / Advances in Environmental Biology.
The spring piston airgun generates power using a powerful spring-loaded piston that is housed within a compression chamber. Cocking the gun (using a break barrel, side lever, or under lever mechanism) causes the piston assembly to compress the spring. When the spring is released it pushes the piston forward compressing a column of air in the chamber behind the pellet.
A pump piston is a moving component that uses piston rings to create a seal, and transfers force in order to eject or compress fluid in the cylinder. Reciprocating pumps are either duplex (two cylinders) or triplex (three cylinders).