Abstract: The present invention embodiments provide a barrel component with the forward under-portion of the barrel configured in various manners. For example, the configurations may include an upward displacement, or angular or radial contouring, of barrel material at the forward underside of a barrel component understation or projection. These configurations provide clearance to allow the barrel to bypass frame-mounted impediments to blank-fire, and permit proper timing and coordination of rearward barrel motion under impact of the recoiling slide and the resultant barrel drop into recoil position without interference with, or re-capture by, the reciprocating slide component. In addition, the blank-fire barrel may be configured to incorporate a laser device for marksmanship training and conducting realistic tactical training exercises.

Abstract: A firearm barrel assembly having a gun barrel with a muzzle opening on a distal end, a shroud coaxially surrounding at least a portion of the barrel, the shroud having a distal portion extending beyond the muzzle opening defining a shroud front region having a distal end portion, a proximal portion extending proximally from the muzzle opening defining an annular region between the barrel and shroud, the shroud front region and annular region in fluid communication with substantially no obstruction between the shroud front region and the annular region, and a front wall disposed at the distal end portion of the shroud. The wall has an opening to allow passage of a projectile fired from the firearm.

Abstract: A muzzle attachment system for a firearm includes a muzzle attachment having a first engagement means, and a muzzle distal portion including a second engagement means, the second engagement means being complementary with the first engagement means. The first and second engagement means cooperate to releasably secure the muzzle attachment to the muzzle distal portion. The first and second engagement means preferably include complementary coarse threaded engagement portions, an annular grooved surface having a plurality of grooves, a grooved surface engagement mechanism, and first and second position stops that abut to form a gas seal. The muzzle distal portion is preferably a flash suppressor, including at least two elongated ports substantially equally skewed from normal relative to a firing axis of the firearm, and substantially evenly distributed around the circumference of the flash suppressor.

Abstract: A firearm for implementing an improved 9mm cartridge is provided, wherein the improved 9mm cartridge includes a 9mm bullet associated with a 45-9 cartridge casing, wherein the 9mm bullet weights at least 90 grains and wherein the 45-9 cartridge casing is configured to contain a propellant sufficient to propel the 9mm bullet to a velocity of at least 1600 feet per second. The firearm may include a barrel, wherein the barrel is configured to operably interact with the 9mm bullet and a chamber, wherein the chamber includes at least one chamber portion sized and shaped to operably associate with the 45-9 cartridge casing and a free-bore, wherein the free-bore includes at least one free-bore portion sized and shaped to operably associate with the 9mm bullet.

Abstract: A barrel system for a paintball marker including a breach removably connected to the paintball marker and a composite front detachably connected to the breach. The composite front of the barrel system includes a hollow bore through which a paintball is propelled, a non-metallic inner layer surrounding the bore, and a non-metallic outer layer surrounding the inner layer. The non-metallic inner layer is preferably manufactured from a plurality of unidirectional graphite fibers embedded within an epoxy resin. The non-metallic outer layer is preferably manufactured from a plurality of graphite fibers that are woven together and embedded with an epoxy resin for surrounding and reinforcing the inner layer. The non-metallic inner layer of the composite front is smoothly and continuously tapered to cause the hollow bore to be tapered from a relatively narrow diameter to a relatively wide diameter in the direction of travel of the paintball.

Abstract: A gun barrel for locking spin-stabilized projectiles using a driving band and a sealing ring disposed behind the driving band, the gun barrel comprising a breach area, a rifled barrel part, and a transitional cone disposed between the breach area and the rifled barrel part. In order to achieve a reliable initial seal between the projectile and the profile of the rifled barrel part against hot propulsion charge gases, a smooth barrel section is disposed between the transitional cone connected to the breach area and the rifled barrel part, wherein the interior diameter of the smooth barrel section is greater than or equal to the exterior diameter of the driving band, but is approximately equal to the exterior diameter of the sealing ring, wherein the length of the smooth barrel section corresponds to at least the lengths of the driving band and the sealing ring of the projectile.

Abstract: An improved action for a bolt action rifle. The action includes a receiver containing a bolt; the bolt having two to three locking lugs surrounding a bolt face; and a threaded insert that joins the rifle barrel to the receiver. The insert also includes a series of locking lugs that mate with the locking lugs on the bolt. The position of the insert lugs relative to the barrel will position the bolt face relative to the barrel's chamber when the bolt is closed. Thus, the insert and barrel can properly set the rifle's headspace. The insert and receiver are preferably each provided with a locking lug, that serve to align the axes of the insert and receiver. The threads of the insert and the barrel are co-axial which serves to align the axes of the insert and barrel. Thus, assembled, the receiver, insert and barrel will be substantially co-axial.

Abstract: A method for setting a protective coating on the inner wall of a tube includes providing a cylindrical sleeve, then setting on the outer surface of the sleeve a layer of a thermo fusible material, then machining the sleeve to provide it with an external diameter corresponding to the tube internal diameter, positioning the sleeve in the tube, and finally soldering the sleeve on the tube by applying heat.

Abstract: A method for manufacturing double barrel shotgun barrels, including the steps of providing an elongated metal stock material having a first end and a second end, forming two index holes in both the first end and the second end of the material, forming a first and second bore hole through the material, and then profiling the material into a desired gun barrel profile. 16. Double barrel shotgun barrels formed from a single piece of elongated solid metal stock material according to the process of the invention are also taught.

Abstract: A firearm barrel assembly having a gun barrel with a muzzle opening on a distal end, a shroud coaxially surrounding at least a portion of the barrel, the shroud having a distal portion extending beyond the muzzle opening defining a shroud front region having a distal end portion, a proximal portion extending proximally from the muzzle opening defining an annular region between the barrel and shroud, the shroud front region and annular region in fluid communication with substantially no obstruction between the shroud front region and the annular region, and a front wall disposed at the distal end portion of the shroud. The wall has an opening to allow passage of a projectile fired from the firearm.

Abstract: A dynamic process for increasing the wear life of ferrous articles subjected to a high-temperature environment created by combustion of a propellant or fuel comprises selecting the propellant or fuel so that its combustion products include relatively large amounts of nitrogen, which nitrogen forms a protective nitride layer on the surface of the ferrous article. Disclosed is a specific embodiment of the invention for prolonging the wear life of gun barrels.

Abstract: A multi-purposes mechanism for shooting apparatus includes a gun body, a barrel, a shooting member, and a rear cap. The gun body comprises a hollow tube perpendicularly interconnecting with a first loading hole at a center portion of the hollow tube. A first stage is formed on an inner wall of the tube in front of the first loading hole. A second stage is formed on the inner wall of the tube in back of the first loading hole. The barrel is disposed in the tube before the first loading hole, and has a first engaging ring corresponding to the first stage of the tube. The shooting member is disposed in the tube after the first loading hole, and has a second engaging ring on an outer wall thereof corresponding to the second stage of the tube. The rear cap is connected to a rear end of the tube.

Abstract: Practice barrels for use with practice cartridges are described herein. An example practice device for use with self-loading grenade launchers includes a practice barrel having a practice cartridge chamber to receive a practice cartridge. A live cartridge does not correspond to the practice cartridge chamber. Additionally, the live cartridge is unable to be properly positioned within the practice barrel to prevent ignition of the live cartridge. Further, the practice cartridge chamber is cushioned to substantially absorb a breech energy to substantially prevent damage to the practice barrel.

Abstract: A body of iron, steel or other such ferrous material is protected from thermochemical erosion by a layer of an iron nitride having a relatively low nitrogen content. The atomic percentage of nitrogen in the iron nitride layer is no greater than 20%, and in specific embodiments is in the range of 10-15%. The nitride layer may have a layer of a refractory material deposited thereatop. Some refractory materials include metals such as chromium. The invention has specific utility for protecting gun barrels, turbines, internal combustion engines, drilling equipment, machine tools, aerospace systems and chemical reactors which are exposed to extreme conditions of temperature and pressure. Specifically disclosed is a gun barrel which incorporates the invention.

Abstract: A semi-automatic rifle kit comprises a receiver; first and second bolt assemblies that can be interchangeably inserted inside the receiver when no barrel is coupled to the receiver; and first and second barrels that can be interchangeably coupled to the receiver when no bolt assembly is inserted inside the receiver. The first bolt assembly can be inserted inside the receiver when the first barrel is coupled to the receiver, but not when the second barrel is coupled to the receiver. The second bolt assembly can be inserted inside the receiver when the second barrel is coupled to the receiver, but not when the first barrel is coupled to the receiver. The first bolt assembly and the first barrel are designed for use with a first type of cartridge, but not a second type of cartridge. The second bolt assembly and the second barrel being are designed for use with the second type of cartridge, but not the first type of cartridge.

Abstract: A barrel (14)for a gas powered ball machine of the type used to simulate balls propelled whilst playing ball sports, especially those machines used to propel balls with a raised seam, such as a baseball or softball. The barrel (14) has one or more openings (160) along its cylindrical length that allow expanding gas to escape as a ball is fired from the machine. The openings (160) assist in predicting the pressure and volume of gas required to repeatedly propel a ball at a predetermined speed from the ball machine.

Abstract: A barrel assembly for a weapon, said barrel assembly including a barrel; a plurality of projectile assemblies axially disposed in end to end abutting relationship within said barrel for operative sealing engagement with the bore of the barrel, each projectile including a projectile head and an integral cylindrical spacer portion extending axially and rearwardly from said projectile head; discrete propellant charges accommodated within said cylindrical spacer portion for propelling respective projectile assemblies sequentially through the muzzle of the barrel; ignition means for igniting said discrete propellant charges; and control means for selectively and sequentially actuating the ignition means.

Abstract: A system for fastening the barrel (1) of a rifle with a replaceable barrel, the system consisting of a lock frame (2), into which the barrel socket (5) can be inserted into position and locked by a bolting device. The bolting device consists of a barrel block stop (4) provided at the top of the lock frame (2), a groove (6) in the barrel socket being insertable into the block stop when the barrel is clamped into locked position.

Abstract: A blank cartridge (1) comprises a cartridge casing (2) with a first primer (18); a piston (9) with a head (10) and an arm (11); and an expansion chamber located between said primer (18) and the head of the piston (10), wherein, following detonation of the primer, the piston slidably displaces substantially within the casing (2) of said cartridge (1).

Abstract: A projectile having variable kinetic energy contains multiple propellant charges (14) that are able to be individually selected for ignition. Each charge (14) has a selectable initiator (15) that may be triggered by a wired or wireless firing system, preferably an inductive system, in order to determine the kinetic energy of the projectile. The projectiles are axially stacked for firing from the barrel of a weapon, with nose portion (11) shaped to seal against tail portion (12) of a leading projectile. Ignition gas exit ports (17) are located in nose portion (11) for propulsion of a leading projectile from the weapon. Alternative, the ports may be located in tail portion (12) for propulsion of each respective projectile. Charges (14) may be distributed around the longitudinal axis of body (10) of the projectile.

Abstract: A method for making a gun barrel for soft projectiles includes providing a mandrel for the bore of the barrel. The mandrel is inserted into a barrel base that can be connected in use to the receiver of a soft-projectile gun. The connected barrel base and mandrel are inserted into a tube. A resin, preferably reinforced, is poured into the space between the inside of the tube and the mandrel. The barrel base, mandrel and tube are surrounded by a pressure chamber. A vacuum is applied to the pressure chamber to de-gas the resin. Then a positive pressure is applied to the pressure chamber to force the tube against the mandrel and resin to form the desired barrel. The mandrel may have rifling impressions. The tube may have a mold shape for forming an ornamental design in the outside of the barrel. Barrels made by the method are also disclosed.

Abstract: A gun having a firing mechanism and a barrel. The barrel has a breech end coupled to the firing mechanism, a muzzle end, and a bore having a length which extends longitudinally between said breech and muzzle ends. The length of the bore between the breech and muzzle ends is curved.

Abstract: A system that converts an original equipment (OEM) AR-15 rifle to a rifle capable of firing cartridges of at least two different calibers. Two or more barrel liners are provided for cartridges of differing calibers. Each liner is insertable through a rear opening of an upper receiver portion of the rifle and into a smooth bore barrel of a modified barrel assembly. Each liner comprises a tube portion having a longitudinal bore and a head portion with an opening that communicates with said bore. An adapter bolt carrier assembly is substituted for the OEM AR-15 bolt carrier assembly. The substituted assembly includes a bolt that carries the firing pin and is slidably mounted on a rail guide. A front end of the rail guide has a tongue extension with a slot that receives a pin attached to a rear end of a liner head. A support rail is fixed to a rear end of the rail guide. A spring extends from the support rail to the bolt, thereby pressing the bolt against the liner head.

Abstract: A method for manufacturing double barrel shotgun barrels, including the steps of providing an elongated metal stock material having a first end and a second end, forming two index holes in both the first end and the second end of the material, forming a first and second bore hole through the material, and then profiling the material into a desired gun barrel profile. 16. Double barrel shotgun barrels formed from a single piece of elongated solid metal stock material according to the process of the invention are also taught.

Abstract: A weapon (104) including a stock, a barrel assembly (105) slidably mounted on said stock whereby, on discharging said weapon, the barrel assembly (105) slidably recoils relative to said stock, and a damper (107) for decelerating the recoiling barrel assembly, wherein said barrel assembly (105) includes a plurality of projectiles axially disposed within a barrel (108) wherein each of said projectiles is associated with a discrete propellant charge for propelling said projectile from the barrel. Suitably the weapon further includes a breech block (109) which slidably recoils relative to said stock and a further damper (106) for decelerating the recoiling breech block.

Abstract: A rifle with a replaceable barrel with two or more barrels for different purposes and calibres and with own cases for different cartridges. At least one barrel (1) has the cavity (2), into which a projection or upper edge (4) in the cartridge case (3) corresponding to the barrel fits, when the correct case has been inserted into the rifle.

Abstract: A blank firing barrel for use with handguns is disclosed. The blank firing barrel is sized to be substituted for an existing live-ammunition firing barrel in a handgun. The blank firing barrel can be machined from a solid block of metal such as stainless steel so that the barrel end is a contiguous portion of the original solid metal block. A downwardly angled small pressure release hole can be drilled into the closed end so that gasses from firing the blank can be safely discharged. The open end of the blank firing barrel can be sized to only accept ammunition being smaller in diameter than regular ammunition that is used for the handgun. The under rear edges of the blank firing barrel can be angled so that said barrel safely recoils within the handgun when it is fired.

Abstract: A system for fastening the barrel (1) of a rifle with a replaceable barrel, the system consisting of a lock frame (2), into which the barrel socket (5) can be inserted into position and locked by a bolting device. The bolting device consists of a barrel block stop (4) provided at the top of the lock frame (2), a groove (6) in the barrel socket being insertable into the block stop when the barrel is clamped into locked position.

Abstract: New design for semi-automatic weapon for several tubes cartridges loading system for long guns, wherein an in-between connection steel part fixes the barrel to the receiver. The retention of the cartridges inside the parallel tubes is done by three metallic nails. The springs of the loading tubes push the cartridges into the cylinder inside the gun through three openings made into the front side of the receiver under the barrel. The rotation mechanism of the cylinder is a result of changing the movement of the bolt from horizontal into vertical.

Abstract: Disclosed herein is a method that relates to resetting and firing a powder actuated setting tool. The method includes resetting the tool by torsionally urging a portion of a firing pin into axial alignment with a finger of a barrel of the tool and compressing the barrel of the tool toward a housing of the tool. The resetting further includes the finger urging the portion of the firing pin to a ready position in response to the compression of the barrel. The method further includes firing the tool by rotating a rotator and the firing pin to a position where the portion of the firing pin is unsupported by the finger.

Abstract: A firearm cartridge has a case configured with a relatively straight-walled portion and a shoulder portion for housing a quantity of propellant. The case further includes a neck for retaining a bullet. The straight-walled portion defines a base cavity having an interior base diameter. The interior base diameter is approximately twice or more the neck diameter. The diameter ratios of the base and neck optimize combustion efficiency to reduce heat and acceleration losses. The cartridge body cavity is sized and configured to contain a sufficient quantity of propellant such that igniting the propellant causes formation of a propellant plug having a diameter that is approximately the diameter of the bullet, and wherein the propellant plug shears free from unburned propellant that is disposed adjacent the relatively straight-walled body portion.

Abstract: A dynamic process for increasing the wear life of ferrous articles subjected to a high-temperature environment created by combustion of a propellant or fuel comprises selecting the propellant or fuel so that its combustion products include relatively large amounts of nitrogen, which nitrogen forms a protective nitride layer on the surface of the ferrous article. Disclosed is a specific embodiment of the invention for prolonging the wear life of gun barrels.

Abstract: A shotgun has two or more firing chambers, each chamber having an exit opening, and a single barrel. A transition connects the exit openings of the firing chambers to the barrel. A movable cover is positioned over or adjacent to the exit opening of at least one of the plurality of firing chambers and can be moved to be positioned over the exit opening of another of the firing chambers.

Abstract: A firearm cartridge has a case configured with a relatively straight-walled portion and a shoulder portion for housing a quantity of propellant. The case further includes a neck for retaining a bullet. The straight-walled portion defines a base cavity having an interior base diameter. The interior base diameter is approximately twice or more the neck diameter. The diameter ratios of the base and neck optimize combustion efficiency to reduce heat and acceleration losses. The cartridge body cavity is sized and configured to contain a sufficient quantity of propellant such that igniting the propellant causes formation of a propellant plug having a diameter that is approximately the diameter of the bullet, and wherein the propellant plug shears free from unburned propellant that is disposed adjacent the relatively straight-walled body portion.

Abstract: The present invention comprises a pneumatic paintball marker for use with an adaptor, the pneumatic paintball marker comprising a marker body which has a back portion and a front portion. The back portion is adapted to receive a paintball and the front portion is adapted to detachably connect with a barrel to discharge a paintball through the barrel. The barrel comprising a hollow elongated cylindrical tube, which comprises an interior diameter, a breech end and a connection means at the breech end and adapted for connection with the front portion of the marker and a paintball discharge muzzle end.

Abstract: A safety system for preventing a handheld firearm from discharging an inadvertently loaded live ammunition projectile or bullet during a training exercise or the like by safely venting through a series of substantially perpendicular vent holes in the barrel, the pressure needed to propel the bullet down and through the barrel towards the target—so as to retain the bullet in the bore and cause the firearm to shut down.

Abstract: Gas-operated automatic and semi-automatic guns are improved by providing their barrels with unique exterior surface configurations to reduce the weight of their barrels while retaining the barrels' original stiffness and to cause the barrels to dissipate heat faster.

Abstract: A tube and ring assembly is provided for use with a shotgun barrel including a cylindrical tube, which may be a conventional choke tube or a carrier platform, with a first externally threaded portion at one end for threadingly engaging an internal thread in the shotgun barrel. A second externally threaded portion is provided on the tube which will remain exposed beyond the muzzle end of the shotgun barrel when the tube is fully threaded into engagement with the shotgun barrel. An internally threaded ring is also provided which is sized to be threadingly carried on an outside of the tube and to engage the second externally threaded portion of the tube such that the ring can be threaded onto the tube until it abuttingly engages the muzzle end of the shotgun barrel.

Abstract: An apparatus for the section-wise autofrettage of gun barrels (22) by a hydraulic pressure generated inside the barrel. The apparatus (1, 1?, 1?) comprises a mandrel-shaped insert (2, 2?, 2?) inserted into the barrel (22) from the breech opening. A first sealing device (3) is disposed at one end of the insert (2, 2?, 2?), and has a seal packet (5) disposed on a seal seat (4) of the insert (2, 2?, 2?). The seal seat (4) is limited at the front by a threaded sleeve (7) screwed onto the insert (2, 2?, 2?), and an annular intermediate part (8) adjoining the threaded sleeve (7) at the rear. The seal packet (5) includes at least one O-ring (10) held by a shoulder (9) of the mandrel-shaped insert (2, 2?, 2?), and a high-pressure seal (15) formed by two partial rings (13, 14) that are connected to one another by a conical contact surface (16).

Abstract: A spring, which may be either a coil spring or a leaf spring, provides an adjustable stabilization force to the barrel of a rifle to tune out harmonic vibrations resulting from firing a particular bullet from the weapon. This tuning enables the scatter pattern for any bullet fired from any rifle to be significantly tightened from the resultant improved accuracy of the weapon.

Abstract: To make a composite gun barrel, an inner barrel of a hard refractory material is formed and a composite jacket formed over it to increase the stiffness and strength while not adding excessive weight. The tows in the external jacket are varied in pitch along the barrel to decrease the amplitude of vibrations of a muzzle during firing. High thermal conductivity material is added to the resin to increase thermal conductivity. In the preferred embodiment, the thermally conductive material is chopped pitch-based carbon fibers and these are randomly oriented. A gas port is added and shielded from the composite material and a metal muzzle piece protects the composite from hot gases.

Abstract: A firearm comprising a gun barrel for accommodating a desired round of ammunition having a bullet, a shell casing and a primer. The gun barrel has a firing pin associated with a chamber of the gun barrel and the firing pin is activated by a trigger assembly. When the firing pin is activated by the trigger assembly, a striking surface of the firing pin strikes the primer and discharges the round of ammunition to propel the bullet out of the opposite end of the gun barrel. The firing pin, the interior surface of the barrel, or some other surface which contacts the shell casing carries a unique identifying indicia. Upon discharge of the round of ammunition, the component of the firearm carrying the unique identifying indicia transfers an impression of the unique identifying indicia to an exterior surface of the shell casing to identify that the shell casing was discharged by that firearm.

Abstract: An assembly (10) having an outer barrel (12) and an inner barrel (30) having a pair of dissimilar sized bearings (38, 40) which are press fit within the outer barrel (12) and which permit the inner barrel (30) to mechanically rotate by the use of a motor assembly (50), a gear assembly (52), a battery (92), a gear (36), and a switch (54) having a depressible plunger (56) and a method for increasing the accuracy of a paint projectile by use of the assembly 10.

Abstract: The present invention provides a gun chamber configured for accepting an efficient gun cartridge where the efficiency of the gun cartridge is determined by determining the water weight volume of the cartridge; determining the bore diameter of the gun barrel; determining the weight of the bullet; and calculating the efficiency rating of the cartridge by multiplying the water weight volume by the bore diameter and dividing by the bullet weight. The efficiency rating is optimal between 110 and 145 when the water weight volume is determined in grains, the bore diameter is determined in thousandths of inches and the bullet weight is determined in grains. One such 50 caliber gun cartridge has a casing diameter of approximately 0.688 inches and neck portion which accepts a bullet having a bore diameter of approximately 0.510 inches. The case has a length ranging from 1.90 inches to 2.5 inches measured from the primer to the mouth of the neck.

Abstract: A chambering device for a gun includes a shank having a plurality of cutting flutes, a projection extending from one end of the shank, at least one spacer disposed about the projection, and a shaft extending from the shank opposite the projection and adapted to rotate the shank along an interior of the barrel of the gun for enlarging the interior and providing a desired head spacing.

Abstract: A method of machining a chamber in a gun barrel by EDM, by using a conductive electrodes which defines the desired shape and dimensions of the chamber. A series of electrodes of progressively increasing diameter may be used. An electrode for an EDM barrel chambering process is an axisymmetrical conductive member, and may include a body, an angular shoulder, a neck, throat area, and a tapered lead angle portion into the bore along with other features of a selected cartridge chamber.

Abstract: The invention pertains to a method for producing a barrel marking on the inner side (4) of the barrel (2) of a firearm. Barrel markings on firearms are used for marking projectiles fired from the respective firearm and to thusly allow a largely definitive allocation of a projectile to the weapon from which it was fired. The invention is characterized by the fact that at least one groove which follows the rifling (5) of the barrel is mechanically produced in the barrel wall by means of a finger-like tool (1) that can be displaced relative to the longitudinal axis (6) of the barrel and turned about the longitudinal axis of the barrel, namely after the inner side of the barrel (2) is finished, preferably during the manufacture of the barrel. The invention also pertains to thusly manufactured barrels and to a device for carrying out said method.

Abstract: A computer-controlled laser etching probe etches a firearm-identifying indicia such as a barcode encoded serial number into the barrel and breech of a bore of a firearm. Owner registration data coupled with the serial number is stored in a central database. A computer-controlled scanner reads the barcode from a slug or casing or a bullet fired from an etched firearm for comparison with registration data in the central database, thereby identifying the registered owner of the firearm from which the bullet was fired. Crime scene data including GPS data identifying the location of the crime, barcoded slugs or casings, registration data associated with the identified firearm, and the last known residence of the registered owner along with derived data may be used to determine a probability map of the location of a criminal suspect.

Abstract: An apparatus and method for crowning a muzzle end of a firearm barrel includes inserting an elongated rod-like pilot stem with upper and lower ends into a barrel bore. The stem has an expandable collet slidably received thereon and a nut threadably attached to the lower end. A deformable body is attached to the nut to frictionally engage a bore wall to prevent rotation of the nut and permit rotation of the stem to expand the collet into contact with the bore wall. A cutting tool is rotated on the upper end of the stem to cut an end surface of the muzzle end.

Abstract: A barrel with an adjustable bore diameter for use with a paint ball gun allowing the gun to fire paint ball pellets of different sizes. The barrel need not be removed from the gun in order to adjust the bore diameter, but rather an outer sleeve of the barrel is rotated to facilitate the change in the bore diameter. In one embodiment, the barrel includes an inner-bore sleeve, a barrel body having openings and force elements received in the openings. The barrel body and force elements are located between the inner-bore sleeve and outer sleeve. One embodiment includes recesses on an inner surface of the outer sleeve to rotationally index the force elements in the outer sleeve.