MO Rev Stat § 571.010 (2021)
2021 Missouri Revised Statutes|Title XXXVIII - Crimes and Punishment; Peace Officers and Public Defenders|Chapter 571 - Weapons Offenses|Section 571.010 - Definitions.

Effective - 28 Aug 2008   571.010. Definitions. — As used in this chapter, the following terms shall mean:  (1) "Antique, curio or relic firearm", any firearm so defined by the National Gun Control Act, 18 U.S.C. Title 26, Section 5845, and the United States Treasury/Bureau of Alcohol Tobacco and Firearms, 27 CFR Section 178.11:  (a) "Antique firearm" is any firearm not designed or redesigned for using rim fire or conventional center fire ignition with fixed ammunition and manufactured in or before 1898, said ammunition not being manufactured any longer; this includes any matchlock, wheel lock, flintlock, percussion cap or similar type ignition system, or replica thereof;  (b) "Curio or relic firearm" is any firearm deriving value as a collectible weapon due to its unique design, ignition system, operation or at least fifty years old, associated with a historical event, renown personage or major war;  (2) "Blackjack", any instrument that is designed or adapted for the purpose of stunning or inflicting physical injury by striking a person, and which is readily capable of lethal use;  (3) "Blasting agent", any material or mixture, consisting of fuel and oxidizer that is intended for blasting, but not otherwise defined as an explosive under this section, provided that the finished product, as mixed for use of shipment, cannot be detonated by means of a numbered 8 test blasting cap when unconfined;  (4) "Concealable firearm", any firearm with a barrel less than sixteen inches in length, measured from the face of the bolt or standing breech;  (5) "Deface", to alter or destroy the manufacturer's or importer's serial number or any other distinguishing number or identification mark;  (6) "Detonator", any device containing a detonating charge that is used for initiating detonation in an explosive, including but not limited to, electric blasting caps of instantaneous and delay types, nonelectric blasting caps for use with safety fuse or shock tube and detonating cord delay connectors;  (7) "Explosive weapon", any explosive, incendiary, or poison gas bomb or similar device designed or adapted for the purpose of inflicting death, serious physical injury, or substantial property damage; or any device designed or adapted for delivering or shooting such a weapon. For the purposes of this subdivision, the term "explosive" shall mean any chemical compound mixture or device, the primary or common purpose of which is to function by explosion, including but not limited to, dynamite and other high explosives, pellet powder, initiating explosives, detonators, safety fuses, squibs, detonating cords, igniter cords, and igniters or blasting agents;  (8) "Firearm", any weapon that is designed or adapted to expel a projectile by the action of an explosive;  (9) "Firearm silencer", any instrument, attachment, or appliance that is designed or adapted to muffle the noise made by the firing of any firearm;  (10) "Gas gun", any gas ejection device, weapon, cartridge, container or contrivance other than a gas bomb that is designed or adapted for the purpose of ejecting any poison gas that will cause death or serious physical injury, but not any device that ejects a repellant or temporary incapacitating substance;  (11) "Intoxicated", substantially impaired mental or physical capacity resulting from introduction of any substance into the body;  (12) "Knife", any dagger, dirk, stiletto, or bladed hand instrument that is readily capable of inflicting serious physical injury or death by cutting or stabbing a person. For purposes of this chapter, "knife" does not include any ordinary pocketknife with no blade more than four inches in length;  (13) "Knuckles", any instrument that consists of finger rings or guards made of a hard substance that is designed or adapted for the purpose of inflicting serious physical injury or death by striking a person with a fist enclosed in the knuckles;  (14) "Machine gun", any firearm that is capable of firing more than one shot automatically, without manual reloading, by a single function of the trigger;  (15) "Projectile weapon", any bow, crossbow, pellet gun, slingshot or other weapon that is not a firearm, which is capable of expelling a projectile that could inflict serious physical injury or death by striking or piercing a person;  (16) "Rifle", any firearm designed or adapted to be fired from the shoulder and to use the energy of the explosive in a fixed metallic cartridge to fire a projectile through a rifled bore by a single function of the trigger;  (17) "Short barrel", a barrel length of less than sixteen inches for a rifle and eighteen inches for a shotgun, both measured from the face of the bolt or standing breech, or an overall rifle or shotgun length of less than twenty-six inches;  (18) "Shotgun", any firearm designed or adapted to be fired from the shoulder and to use the energy of the explosive in a fixed shotgun shell to fire a number of shot or a single projectile through a smooth bore barrel by a single function of the trigger;  (19) "Spring gun", any fused, timed or nonmanually controlled trap or device designed or adapted to set off an explosion for the purpose of inflicting serious physical injury or death;  (20) "Switchblade knife", any knife which has a blade that folds or closes into the handle or sheath, and:  (a) That opens automatically by pressure applied to a button or other device located on the handle; or  (b) That opens or releases from the handle or sheath by the force of gravity or by the application of centrifugal force. ­­-------- (L. 1981 H.B. 296, A.L. 1998 S.B. 496, A.L. 2008 H.B. 2034)