Gas
Gas-powered Airsoft rifles propel plastic BBs using a pressurized gas.
Common Gases
Gases commonly used include "green gas," HFC134a, CO2 and nitrogen.
Fire Style
A gas-powered Airsoft gun may be either semiautomatic or fully automatic, depending on the model.
Blowback
One of the features of some gas Airsoft rifles in particular is "blowback," which uses some of the pressurized gas to simulate a recoil when firing.
Legal Concerns
The legality of Airsoft guns can vary greatly across jurisdictions. You should discover how your locality regulates imitation firearms such as Airsoft rifles before purchasing one.