Armor-Piercing Bullets Act of 2015

Amends the federal criminal code to provide that: (1) a .22 caliber projectile that would otherwise constitute "armor piercing ammunition" shall be considered to be primarily intended to be used for sporting purposes (and thus excluded from the definition of "armor piercing ammunition" for purposes of federal firearms provisions) if the projectile weighs 40 grains or less and is loaded into a rimfire cartridge, and (2) a projectile that would otherwise constitute "armor piercing ammunition" shall be considered to be primarily intended to be used for a sporting purpose if the projectile is loaded into a cartridge for which the only handgun that is readily available in the ordinary channels of commercial trade is a single shot handgun.

Defines a "single shot handgun" as a break-open or bolt action handgun that can accept only a single cartridge manually and that does not accept or use a magazine or other ammunition feeding device, excluding a pocket pistol or derringer-type firearm.

Authorizes the Attorney General to treat a projectile as not primarily intended to be used for sporting purposes if substantial evidence exists that the projectile is not primarily intended to be used for such purposes.