Abstract: Method and apparatus are disclosed for launching electrified projectiles from a firearm (preferably, a shotgun) by using a specially designed breech bolt which also prohibits firing lethal ammunition. The preferred method comprises: opening a receiver of a shotgun by retracting a breech bolt having a central protrusion on a leading end; inserting a cartridge, having an electrified projectile, into a breech of the firearm; wherein the electrified projectile contains a primer and adjacent pyrotechnic propellant; nesting an end portion of the cartridge within the protrusion of the bolt; propelling the electrified projectile from the firearm by striking a firing pin of the shotgun against the primer, thereby igniting the pyrotechnic propellant, of the nested electrified projectile; and prohibiting, by the central protrusion of the bolt, the firing of lethal ammunition from the firearm.

Abstract: A weapon conditionally activates a cartridge. The cartridge has a projectile and a first mechanical feature. The weapon includes an activator and a station. The activator includes a second mechanical feature. The station positions the cartridge so that the first feature opposes the second feature. On condition that the first feature does not mechanically interfere with the second feature, the activator activates the cartridge to launch the projectile from the cartridge. On condition that the first feature mechanically interferes with the second feature resulting in an excess head space, the activator is inhibited by the excess head space from activating the cartridge.

Abstract: Method and apparatus are disclosed for launching electrified projectiles from a firearm (preferably, a shotgun) by using a specially designed breech bolt which also prohibits firing lethal ammunition. The preferred method comprises: opening a receiver of a shotgun by retracting a breech bolt having a central protrusion on a leading end; inserting a caitiidge, having an electrified projectile, into a breech of the firearm; wherein the electrified projectile contains a primer and adjacent pyrotechnic propellant; nesting an end portion of the cartridge within the protrusion of the bolt; propelling the electrified projectile from the firearm by striking a firing pin of the shotgun against the primer, thereby igniting the pyrotechnic propellant, of the nested electrified projectile; and prohibiting, by the central protrusion of the bolt, the firing of lethal ammunition from the firearm.

Abstract: A weapon conditionally activates a cartridge. The cartridge has a projectile and a first mechanical feature. The weapon includes an activator and a station. The activator includes a second mechanical feature. The station positions the cartridge so that the first feature opposes the second feature. On condition that the first feature does not mechanically interfere with the second feature, the activator activates the cartridge to launch the projectile from the cartridge. On condition that the first feature mechanically interferes with the second feature resulting in an excess head space, the activator is inhibited by the excess head space from activating the cartridge.

Abstract: A weapon conditionally activates a cartridge. The cartridge has a projectile and a first mechanical feature. The weapon includes an activator and a station. The activator includes a second mechanical feature. The station positions the cartridge so that the first feature opposes the second feature. On condition that the first feature does not mechanically interfere with the second feature, the activator activates the cartridge to launch the projectile from the cartridge. On condition that the first feature mechanically interferes with the second feature resulting in an excess head space, the activator is inhibited by the excess head space from activating the cartridge.

Abstract: A weapon conditionally activates a cartridge. The cartridge has a projectile and a first mechanical feature. The weapon includes an activator and a station. The activator includes a second mechanical feature. The station positions the cartridge so that the first feature opposes the second feature. On condition that the first feature does not mechanically interfere with the second feature, the activator activates the cartridge to launch the projectile from the cartridge. On condition that the first feature mechanically interferes with the second feature resulting in an excess head space, the activator is inhibited by the excess head space from activating the cartridge.

Abstract: A display clamp assembly, and a related method, are disclosed for removably attaching a second barrel to a shotgun for display purposes, allowing a retail store (or a buyer) to display the firearm as a combination unit in a display case. The extra barrel is attached onto and substantially parallel to the barrel of the fully assembled shotgun. In the preferred embodiment, the display clamp is longitudinally split into two halves. The two halves are mirror images that can be bolted together, along their midsections. When joined, the two halves form collars on opposite ends. One collar is designed to snugly fit around the barrel of an assembled shotgun. The second collar has flared ends that guide the second barrel into the clamp.

Abstract: A firearm, such as a shotgun, is normally-enabled at all times for firing. An authorized user, such as a police officer, wears a transmitter that transmits signal energy in all directions. The transmitter may be worn by the authorized user on the user's person. The transmitter transmits a "disable" system that is received by a corresponding signal receiver built into the firearm only when the muzzle of the firearm is pointed in the direction of the authorized user. That is, the receiver has a narrow angular spatial range of signal reception. In this way, if the firearm is taken away from the authorized user, or the authorized user accidentally points the firearm at his/her person, then the firearm will be disabled automatically from firing by reception of the "disable" signal sent by the transmitter worn by the authorized user.

Abstract: Gases of combustion vented from the bore of a shotgun barrel in spaced relation to the muzzle travel along one or more passageways externally of the barrel and are discharged externally of the barrel and ahead of the muzzle in a generally transverse direction relative to the barrel axis to create turbulence immediately forward of the muzzle and exert lateral forces on a shot charge after the charge leaves the muzzle whereby the short range shot pattern produced by the barrel is substantially enlarged. A finite, moveable mechanical obstruction projecting into the bore retards the advance of a wad to reduce influence of the wad on the shot charge.

Abstract: A choke tube assembly having a rear part and a front part selected from a plurality of front parts is releasably retained within a stepped cylindrical bore in the muzzle end of a shotgun barrel. The front and rear parts cooperate to define a forwardly converging forcing cone contiguous to a cylindrical choke bore which opens through the forward end of the front part. Each of the front parts define a choke bore of a different diameter. The shot pattern characteristics of the gun barrel may be altered by substituting one front part for another having a different choke characteristic.

Abstract: A forearm assembly for a pump action shotgun includes an axially elongated forearm and a pair of action bars. The forward end of each action bar is received and retained within an associated complementary recess in the rear end portion of the forearm. A piston grip comprises part of the forearm assembly and is releasably secured in fixed position to the forearm in a selected one of a plurality of angularly spaced apart mounting positions by a single fastener to accommodate either a right or left handed shooter.

Abstract: A firearm lock assembly includes a trigger blocking element and a cable lock which passes through the receiver to secure the breech bolt of the firearm in an open condition and which cooperates with the trigger blocking element to lock the trigger in a disabled condition.

Abstract: A firearm lock resembling a high security padlock of conventional type secured to an associated firearm to disable the firearm. The key for releasing the locking mechanism to enable the lock to be removed from the firearm comprises a live round of ammunition for the firearm which may be discharged in the firearm after the lock has been removed.

Abstract: A firearm having a movable barrel including an axially elongated smooth bore. The barrel moves in an axial direction and simultaneously rotates about its axis when a round of slug ammunition is discharged by the firearm whereby to impart rotary motion to the slug as it travels through the bore so that the slug is rotating about its axis of trajectory as it leaves the muzzle of the firearm and travels toward a target.