The single action revolver has remained popular for its historic appeal, reliable design, and uncanny balance. For some reason a single action Colt 45 is easier to shoot from the hip than a modern revolver, and is used almost exclusively in trick shooting.
Semiautomatic versions of submachine guns (such as the Uzi) are classed as pistols for legal reasons. These often have the ability to hold 20 to 30 rounds, but are otherwise identical to conventional handguns in similar caliber. The expense of such weapons precludes their use by most criminals, but they may be used by persons involved in organized crime, drug-dealing, and gangs.
Air guns which use pneumatic pressure to fire a projectile are generally known as "BB guns" and have been around for over 200 years. Three mechanisms are employed:
Even though cheap "Saturday night specials" are readily available, youths and youth gang members may attempt to build their own firearms. Typically, they are crude, and adapted to fire available ammunition. In one study, such guns caused unusual muzzle imprints, intensive soot deposits at the entrance wounds and on the hands, intensive CO-effects, burns, and in one case a skin laceration of the hand holding the weapon. The bullets showed a reduced penetration depth, and characteristic firing marks were missing. (Karger et al, 1995)
Lastly, there has arisen a new group of handguns for hunting big game and long range target competition that are nothing but single shot rifles with shortened barrels and no buttstock. These shoot rifle or hybrid rifle cartridges and deliver rifle energies.