Abstract: Firearm of muzzle-loading type is constructed to provide ready attachment of different barrels, such as a rifle or shotgun barrel, having different sizes to the same butt stock. The butt stock is provided with a mounting plate on its front end which is threadably engaged by an adapter member secured to the breech end of the barrel. The adapter member has a rear plate portion which matches the shape of and is co-extensive with the mounting plate, and abuts the same in operative position. Yieldable locking means on the adapter member provides for ready locking and unlocking of the adapter member and mounting plate. Assembly of the barrel to the butt stock is made by screwing the adapter member into the mounting plate and locking the parts together in operative position.

Abstract: This invention is designed for the conversion of the Mini-14 and AC-556 family of firearms as manufactured by the Sturm Ruger and Co., Inc. in Southport, Conn., for firing of smaller, less powerful ammunition for which it was not originally designed, by providing a conversion bolt assembly, auxiliary chamber assembly, operating rod assembly and magazine. The invention may also be employed in other firearms of similar construction without departing from the intent and scope of this invention.

Abstract: A cartridge shaped barrel insert is described that can be used as the barrel of a pistol and as a rimfire cartridge insert for a large bore weapon. The cartridge insert includes an internal secondary firing pin that can be actuated to fire a rimfire cartridge by a hammer on the pistol frame or by the usual hammer and center fire mechanism of a large bore weapon. A resilient pad within the insert yieldably urges the secondary firing pin away from the breech end of the barrel. A cap can be placed over the bullet of the rimfire cartridge to match the bore of a large bore center-fire weapon. When the cartridge is fired, the rimfire bullet and cap will be driven by expanding gases along the weapon barrel, with the barrel bore guiding the cap and bullet in the same manner as a conventional large bore bullet.

Abstract: A firearm capable of firing different-sized cartridges by the use of a detachable chamber having a plurality of bores extending therethrough. Each bore is adapted to receive a different-sized cartridge. The chamber is carried on a firearm receiver and can be positioned such that any one of the aforesaid bores in the chamber is aligned with the axis of the receiver.

Abstract: The present invention relates to a caliber reducer for hand weapon.The caliber reducer comprises a caliber reducing tube 13 with a boring 14 the axis B'-B' of which is situated in the barrel boring diametral plane passing by the line of sight of the weapon and is characterized in that the reducing tube boring axis B-B' diverges relative to the barrel axis A-A in the direction of the muzzle.The object of the invention is to preserve the holding of the weapon despite the suppression of the kick due to the reduced caliber, by compensating for the divergence of the line of sight.

Abstract: A caliber-reducing adaptor kit for a revolver having an original revolver barrel, and a cylinder with a chamber having a powder-receiving compartment at one end. A substitute barrel, having a reduced caliber bore, is received in and is detachably mounted to the original revolver barrel. A cylinder insert is removably received in the cylinder chamber between the substitute barrel and the powder-receiving compartment, the insert having a caliber bore substantially the caliber of the substitute barrel. The cylinder insert includes a plunger having a head at one end engageable with an end portion of the substitute barrel, and having a shank portion, the bore being provided in the plunger. A sleeve is slidably mounted on the shank portion of the plunger and is engageable with the cylinder adjacent the powder-receiving compartment.

Abstract: An adaptor cartridge permitting the use of rim-fire ammunition in a center-fire weapon. The adaptor comprises a tubular casing with an inner passageway located at an acute angle to the tubular casing at the lower end where the firing pin strikes. The opening of the cylindrically-shaped passage at the lower end crosses the center point of the lower end of the tubular casing so that the centrally-located firing pin of the weapon will strike the rim of an insert blank cartridge which is rim-fired and which has been placed in the adaptor cartridge.

Abstract: A steel plug is inserted into a modern shotgun to convert it into a muzzleloading firearm. The plug is made for use as a breech plug in a single barrel shotgun without modifications to gun. The plug enables the shotgun to be used as a muzzle-loader with black powder and allows conversion of the gun back to its original condition by simply removing the breech plug.

Abstract: A pistol and cartridge shaped barrel insert is described that makes use of a unique center-fire cartridge shaped barrel insert that can be used as the barrel of a pistol and as a rimfire cartridge insert for a large bore weapon. The pistol body includes a frame with an extensible nose piece that allows insertion and removal of the cartridge insert. The cartridge insert includes an internal secondary firing pin that can be actuated to fire a rimfire cartridge by a hammer on the pistol frame or by the usual hammer and center fire mechanism of a large bore weapon. A resilient pad within the insert yieldably urges the secondary firing pin away from the breech end of the barrel.

Abstract: The improved gun barrel insert is provided in tank-borne guns, field howitzers and the like. It makes possible the use of small caliber and thus less expensive ammunition having ballistic properties of the substituted larger caliber ammunition, while maintaining the opening, closing and igniting mechanisms provided for the larger caliber firing as well as the geometry and weight of the larger caliber cartridges. True combat conditions with a correct observation of shooting regulations can thereby be simulated to a very large extent and a high accuracy in hitting targets from shooting stands or moving bases can be obtained. The provided insert accommodates both a smaller-caliber cartridge and the igniting mechanism therefor. The insert is designed as a slightly tapering rotational symmetrical adapter conformable to the cartridge chamber of the larger caliber weapon. The conical front end of the adapter bears against the mating rear portion of the barrel insert proper.

Abstract: A barrel extension for a weapon having a barrel internally threaded at its forward end together with various associated devices including a hand grip and a wrench which includes a tubular member having a smooth bore and an externally threaded end portion threadedly engageable with the threaded forward end portion of the weapon barrel with the barrel extension bore aligned with the barrel bore and including a hollow nightstick having an interior forming a storage cavity for the barrel extension, the nightstick having an internally threaded open end portion for threaded engagement with a threaded portion on a closure member to close the storage cavity in order to transport the barrel extension in a concealed manner.

Abstract: A round of ammunition in which a primer cap provides the sole means for propelling a lightweight missle from a cartridge casing shaped to fit into an existing firearms firing chamber. A removable insert in the cartridge casing 12 provides an elongate passage which moderates the force of the primer cap explosion to avoid damaging the missile. The casing is reloadable from the base to allow a fresh missile to be inserted, and in an alternative embodiment a two part insert is provided which likewise allows a missile to be inserted from the base end. In all embodiments the missile is preferable in the form of an air gun pellet, and the ammunition is preferably used with a liner assembly adapted to minimize damage to the missile.

Abstract: A replaceable barrel which screws into a threaded aperture in the frame of a handgun in the form of a single action revolver is properly positioned with respect to the front sight thereon and rigidly secured to the frame by an arrangement which utilizes the base pin for the cylinder and which includes a lug formed on the outside of the barrel adjacent the frame. The cylinder base pin couples to the lug to provide the barrel with the proper angular position relative to the frame and to index the lug and included barrel relative to the frame to compensate for any play therebetween. In a first arrangement for securing the cylinder base pin to the lug a set screw having a threaded exterior is screwed into a threaded aperture in the lug so as to force a conical shaped end thereof within an aperture for the base pin in the frame while at the same time receiving a necked-down front end of the cylinder base pin within a hollow interior thereof.

Abstract: The hand gun has a barrel tht may threadedly be supported from the hand gun frame and which is covered by a shroud surrounding the barrel and extending substantially the entire length of the barrel from the frame to the barrel end. A barrel to shroud nut secures the shroud in place about the barrel and against the frame and has a conical or spherical surface in engaged cooperation with a like conical or spherical seat in the shroud to accurately concentrically align the barrel within the shroud to provide more accurate firing and in particular rapid firing.

Abstract: A firearm having interchangeable barrels and ammunition cylinders for changing the caliber of ammunition used therewith includes a plurality of ammunition cylinders and a plurality of barrels, each barrel being threadedly mountable on the firearm frame with each barrel including a longitudinal barrel extension for interfering with the mounting and revolution of the ammunition cylinders for ammunition having a larger caliber than that of the respective barrel, and the improvement therein includes alignment marks on the barrels and frame for alignment under the full threaded engagement of each barrel in the frame, a plurality of sight ribs with each sight rib corresponding to a different barrel, means for attaching each sight rib to its corresponding barrel at a predetermined location to enable each sight rib to its corresponding barrel at a predetermined location to enable each sight rib to be operatively oriented with the rear sight for aiming the firearm when each barrel is fully threadedly engaged in the fr

Abstract: A firearm having interchangeable barrels and ammunition cylinders for changing the caliber of ammunition used therewith includes a plurality of ammunition cylinders and a plurality of barrels, each barrel being threadedly mountable on the firearm frame width each barrel including a longitudinal barrel extension for interfering with the mounting and revolution of the ammunition cylinders for ammunition having a larger caliber than that of the respective barrel, and the improvement therein includes alignment marks on the barrels and frame for alignment under the full threaded engagement of each barrel in the frame and forward sights on each of the barrels for cooperation with a rear sight on the frame to allow aiming of the firearm when the barrel is fully engaged in the frame thereby insuring that the weapon will only be used when a barrel is fully threadedly engaged in the frame and therefore that the longitudinal extension thereof will be operative to interfere with any ammunition cylinders intended for larg

Abstract: An automatic pistol of the breech block type which is interconvertible to fire sub-caliber cartridges. The frame, handle, slide, ejector and firing mechanism of the larger caliber pistol are used when converting for sub-caliber usage. A sub-caliber barrel is mounted in the slide and detachably connected to the frame by a pivotal link. An interchangeable barrel bushing adapted to support the forward end of the sub-caliber barrel is inserted in the slide. At the forward end of the slide a recoil spring is tensioned to operate the slide upon firing of a sub-caliber cartridge. A sub-caliber magazine is inserted in the handle. The extractor is cambered and is sufficiently flexible to capture and extract cartridges of both calibers. The cartridge locating recess in the breech face is that of the larger caliber.

Abstract: A cylindrical plug that is configured to be removably inserted into the breech of a breech-loading firearm, converts the firearm to one of a muzzle-loading type. The plug is provided with a primer-receiving chamber at one end, a powder charge chamber at the other end, and a passage that establishes communication between the two chambers. The primer-receiving chamber is adapted to receive a percussion-type primer, detonation of which generates ignition products which are communicated via the flash to a main powder charge situated in the charger chamber of the plug to cause combustion of said charge and propel a projectile or projectiles from the firearm. Alternatively, the plug is structured so that it can function as a reusable casing for holding a powder charge and a projectile or projectiles to function, for example, as a shotgun shell.

Abstract: A conversion plug that is configured to be removably inserted into the breech of a breech-loading firearm, converting the firearm to one of a muzzle-loading type. The plug is provided with a primer-receiving chamber at one end and a series of passages that communicate the chamber to a region proximate the other end. The primer-receiving chamber is adapted to receive a percussion-type primer, detonation of which generates ignition products which are communicated via the series of passages to a main powder charge situated at the interior end of the plug to cause combustion of said charge and propel a projectile from the firearm.

Abstract: Conversion plug having the general shape of a shotgun shell, having a large counterbore formed in the end adjacent the hammer and having a small threaded counterbore to receive a nipple adapted to receive a percussion firing element.

Abstract: A conversion system for .30 caliber semi-automatic carbines permits selective use with .22 caliber ammunition. Modified barrel, bolt, operating slide and magazine sub-assemblies easily replace the corresponding original sub-assemblies to provide for direct blow-back operating slide actuation with .22 caliber ammunition. The replacement parts are of such simplified construction as permits manufacturing and sales as a conversion kit at a fraction of the original cost of the .30 caliber carbine to be converted. The conversion technique also provides for the independent manufacture of a unique .22 caliber semi-automatic carbine having the general appearance and "feel" of the standard .30 caliber M1 carbine.

Abstract: A durable plastic sleeve which simulates a larger gauge gun ammunition shell and has forced-fit metal sleeve insert at one end for seating the firing end of a smaller gauge gun shell and has a restricted other end for frictionally gripping the other end of the smaller gauge shell.

Abstract: To reduce the caliber of a muzzle-loading handgun, an inner barrel is inserted into the normal, outer barrel to which it is positively fastened only at the muzzle end. The rear end of the inner barrel adjoins a nipple, screwed into the breech portion of the outer barrel, which has a rearwardly projecting boss adapted to carry a percussion cap lodged in a recess of a hammer when the latter is uncocked. The nipple has a bore offset from or inclined to the barrel axis to reduce the reaction of the explosive charge upon the hammer when the percussion cap is detonated. The inner barrel fits tightly into the outer barrel in the vicinity of the nipple but is of reduced diameter over the greater part of its length for easier insertion.

Abstract: An automatic weapon incorporating a retarded blow back, a cartridge and bolt centering assembly, light weight and minimum component construction, simplicity in disassembly, easily detachable barrel, unique belted ammunition feed system, disposable ammunition box, a guide buffering assembly, muzzle brake, remote firing capability, front sight charging system and a bulkhead recoil absorbing arrangement.

Abstract: A bolt assembly on a rim fire adapter to permit a rifle to use smaller amition wherein an improvement is made to require cocking of the rifle hammer before the bolt can chamber another round and thus avoid the safety hazard of double firing.A bolt extension block having a pivotal extension and extended hammer cocking surface is added to the rear of the bolt to achieve hammer cocking with less bolt recoil travel to insure that doubling or double firing will not occur.

Abstract: An adapter for firing a small caliber round in a large caliber gun. A cardge case which fits a large caliber gun is provided with an internal thread for receiving an adapter sleeve. The adapter sleeve has a bore for receiving a small caliber round and is provided with a locking device for holding a small caliber round in position.

Abstract: A gun barrel having the exterior configuration of at least a portion of its length formed in an oblong shape in which the width of the oblong portion is greater than its height. This configuration permits the interchangeability of a plurality of gun barrels in a common receiver and common fore-end without the presence of a gap between the common fore-end and the smaller outside diameters of the smaller bore barrels since the oblong portions of the smaller bore barrels have a width equal to the outside diameter of the largest bore barrel designed to be interchangeable with the common receiver and common fore-end.