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 flywheel keeps an engine going between the strokes of the piston. That part of a steam-engine in which the steam is utilized to drive the piston. The diameter of piston is four inches and the length of stroke is six inches. The cylinder-end cover should be left until the piston-rod and piston are made.