Which firearm is classified under devices not regarded as firearms?

An air gun is classified under devices not regarded as firearms primarily because it uses compressed air or gas to propel projectiles rather than using the explosive combustion of gunpowder, which is characteristic of traditional firearms. These devices typically operate at lower velocities and are often subject to different regulatory frameworks than firearms.

In many jurisdictions, air guns are considered less lethal and therefore may have fewer restrictions applied to their ownership and use compared to fully automatic firearms, rocket launchers, and self-propelled grenades, all of which employ explosive mechanisms that align more closely with conventional definitions of firearms. As a result, the regulation and classification of air guns differ, making them distinguishable from the more heavily regulated categories of military and automatic weapons.