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.
<br />Spring power: or Nitrogen piston power. this uses a large spring inside an air piston tube; When the barrel is cocked (Commonly called a break barrel rifle) the spring is pushed back in the piston chamber and locks. A pellet or BB is loaded.