What are the major airgun power types?

The four common power types are PCP (pre-charged pneumatic), break barrel (which uses either a coiled spring or a gas piston), multi-pump pneumatic, and CO2.

PCPs store high-pressure air in an onboard reservoir for many shots per fill. Break barrels generate compressed air on each shot by cocking a spring or gas ram. Multi-pumps build pressure with several strokes of an onboard pump. CO2 guns use 12-gram cartridges or larger bulk tanks of liquefied carbon dioxide. Each has different tradeoffs for cost, complexity, power, and shot consistency.