A pen gun is a firearm that resembles an ink pen. [1] [2] They generally are of small caliber (e.g., . 22 LR, .25 ACP, .32 ACP, .38-caliber, etc.) [3] [4] [5] and are single shot. [4] [6] Early examples of pen guns were pinfired, but modern designs are rim or centerfire. [1] Some pen guns are not designed to fire regular cartridges, but rather blank cartridges, signal flares, or tear gas cartridges. [1] [7]
In the United States, pen guns that can fire bullet or shot cartridges and do not require a reconfiguration to fire (e.g., folding to the shape of a pistol) are federally regulated as an Any Other Weapon ( Title II). They require registration under the National Firearms Act and a tax in the amount of five dollars is levied. [7] [8]
According to the FBI, pen guns were widely used for self-defense in the 20th century. [9]