What is an airgun and how is it different from a firearm?

An airgun launches a projectile using compressed gas, compressed air, or a spring-driven piston rather than burning gunpowder.

Federal law (18 USC 921) defines a firearm as a weapon that expels a projectile by the action of an explosive, so airguns sit outside that definition and are regulated more like consumer products at the federal level. They still launch real projectiles at lethal velocities in many cases, so they should be handled with the same discipline as a firearm. State and city rules vary, with New Jersey and Rhode Island treating airguns as firearms and New York City requiring a license.