COMPRESSED GAS GUN

Abstract

A compressed gas gun comprising a chassis, a pellet firing assembly including a breech and a slidable bolt mounted in the chassis, a valve assembly mounted in the chassis, a barrel assembly comprising a barrel, a grip for holding the gun, a trigger assembly comprising a trigger, and a magazine receiver for holding a removable magazine for storing pellets.

Description

FIELD OF THE INVENTION

The invention generally relates to compressed gas-powered guns and more specifically to guns for firing rigid plastic or metallic spherical pellets such as airsoft pellets.

BACKGROUND OF THE INVENTION

Airsoft guns typically fire rigid plastic spherical pellets that are for instance 6 mm in diameter and are typically used for target practice and in mock war games.

Compressed gas-powered guns for the firing of pellets have long been used, generally for the firing of pellets in semi automatic (single pellet fire for each trigger pull), fully automatic (a sequence of rapidly fired pellets being fired while the trigger is held down), or a simultaneous acceleration of multiple pellets in a blast.

In general, airsoft guns have been designed with a modular approach. A separate removable reservoir is used to store gas, compressed to a liquid state, for propulsion. This separate removable reservoir may also include a spring loaded magazine for feeding pellets as a convenient means to reload both propellant and pellets when this assembly is replaced. A significant drawback of this common approach is that the separate propellant reservoir may decrease in temperature rapidly as the gun is fired as heat is required to achieve the phase change necessary to provide compressed gas in what is a single component two-phase pressure system. Generally the heat capacity of the replaceable vessel is not very high and its small surface area does not provide very much area to absorb heat from the environment which results in a rapid drop in temperature of the propellant and a subsequent reduction in saturation pressure of the two-phase propellant system being employed. Typically gas-powered airsoft guns, employing a 2 phase single component pressure system, will operate at the saturation pressure present in the single 2 phase propellant reservoir.

Furthermore the typical removable gas reservoir tends to be received in a sleeve like feature of the gun which will further inhibit the reservoir's ability to absorb heat from the environment via convection.

The typical means to solve this issue of a rapidly cooling source of inconsistent pressure, is to attach an externally regulated pressure source to provide consistent high volumes of propellant. The downside of this approach is that it requires a considerable additional cost of a large pressure vessel and modular regulator and it also requires the use of a hose to conduct gas to the gun which can be cumbersome.

Another draw back of conventional airsoft guns is the poor trigger feedback compared to guns with combustion ammunition.

SUMMARY OF THE INVENTION

An object of the invention is to provide a compressed gas gun which has consistent firing performance.

Another independent object of the invention is to provide a compressed gas gun which has a good tactile feedback.

Another independent object of the invention is to provide a compressed gas gun which allows to control a pattern of dispersion of pellets.

Yet another independent object of the invention is to provide a compressed gas gun which has a high rate of automatic fire.

It is advantageous to provide a compressed gas gun which is economical to produce.

It is advantageous to provide a compressed gas gun which is robust and reliable.

It is advantageous to provide a compressed gas gun which is easy to operate and maintain.

Different objects of the invention have been achieved by the different independent claims. Dependent claims define various advantageous embodiments of the invention.

Disclosed herein is a compressed gas gun comprising a chassis, a pellet firing assembly including a breech and a slidable bolt mounted in the chassis, a valve assembly mounted in the chassis, a barrel assembly comprising a barrel, a grip for holding the gun, a trigger assembly comprising a trigger, and a magazine receiver for holding a removable magazine for storing pellets.

According to a first aspect, the compressed gas gun further comprises:

• • a refillable propellant gas storage reservoir formed within the chassis, and
  • an expansion chamber formed within the chassis, connected to the gas storage reservoir via a pressure regulator for storing expanded gas supplied from the gas storage reservoir, the expansion chamber supplying propellant gas to the pellet firing assembly via the valve assembly.

According to a second aspect, the slidable bolt comprises a bolt nose, a central bolt passage extending through the bolt nose, and a rear bolt chamber fluidly connected to the central bolt passage, the bolt nose comprising bolt nose outlets fluidly connected to the central bolt passage for the passage of propellant gas from a rear end of the bolt through the rear bolt chamber to a breech chamber of the breech.

According to a third aspect, the valve assembly comprises a slidable valve spool engageable by a trigger linkage, the valve spool having a first seal engaging in a fixed first sealing bore on a rear end and a second seal engaging a fixed second sealing bore on a forward end, the first and second seals having the same diameter, wherein the valve spool further comprises a third seal downstream of the second seal and having a slightly larger diameter than the first and second seal, the third seal configured to engage a third sealing bore when the second seal disengages the second sealing bore configured to provide tactile feedback on the trigger of a firing action.

According to a fourth aspect, the compressed gas gun further comprises a pellet dispersing nozzle mounted on an end of the barrel, a barrel bore of the barrel comprising a widening shoulder proximal said end of the barrel on which the pellet dispersing nozzle is mounted, the pellet dispersing nozzle comprising a slightly inwardly constricting tapered bore which is configured to deflect the pellets to increase their dispersion.

According to a fifth aspect, the breech comprises a breech chamber configured to receive a plurality of pellets therein forming spaces therearound for flow of propellant gas towards the barrel bore, an end of the breech chamber interfacing with the barrel bore comprising a detent spring retaining the pellet in the breech chamber with a predefined spring force.

In an advantageous embodiment, the propellant gas storage reservoir and the expansion chamber are bounded by walls of the chassis, the propellant gas storage reservoir refillable through a propellant fill valve accessible by an operator.

In an advantageous embodiment, the propellant fill valve is positioned on and extends through one of said walls of the chassis, preferably a top wall of the chassis.

In an advantageous embodiment, the pressure regulator is adjustable.

In an advantageous embodiment, the chassis has a generally prismatic shape made of an extruded and machined part.

In an advantageous embodiment, the chassis is made of an extruded and machined aluminium part.

In an advantageous embodiment, the barrel assembly, grip, trigger, and magazine receiver are assembled and fixed to the chassis.

In an advantageous embodiment, the bolt comprises an inclined bolt nose tip facing slightly downwardly and forwardly configured to push pellets from the magazine to the breech chamber.

In an advantageous embodiment, the valve assembly comprises a fixed piston comprising a piston probe sealingly insertable in the central bolt passage configured to seal the central passage to block the flow of propellant gas to the breech chamber when the bolt is in a rearward position, and the piston probe configured to disengage the bolt passage when the bolt is in a forward position allowing propellant gas to flow through to the breech chamber.

In an advantageous embodiment, the the constricting tapered bore has a non-axisymmetric shape, or an outlet of the constricting tapered bore has a non-axisymmetric shape, or both the constricting tapered bore and the outlet have a non-axisymmetric shape, configured to disperse pellets propelled out of the barrel in an obround target area.

In an advantageous embodiment, the detent spring comprises or consists of a generally U-shaped spring wireform.

In an advantageous embodiment, the magazine receiver comprises a spring magazine retention element fixed to a side wall of the magazine receiver, the spring magazine retention element having a V shaped finger extending through an orifice in the side wall and configured to engage in a magazine retention window or notch in the side of the magazine.

In an advantageous embodiment, the spring magazine retention element comprises or consists of a stamped and formed spring sheet metal.

In a variant, the compressed gas gun may comprise an external gas supply.

The external gas supply may comprise a bulk storage bottle containing a compressed CO2 or HPA (high pressure air) system worn on a belt or backpack and connected to the compressed gas gun with a hose. Alternatively, the external gas supply may comprise a compressed gas cylinder removably mountable within or onto the chassis, or in the grip of the gun.

In an embodiment, the compressed gas gun comprises an expansion chamber and the external gas supply is connected directly to the expansion chamber to feed gas into the expansion chamber.

BRIEF DESCRIPTION OF THE FIGURES

The foregoing and additional objects, features, and advantages of the present invention will become more readily apparent from the following detailed description of preferred embodiments, made with reference to the accompanying figures, in which:

FIG. 1 is an external perspective view of a compressed gas gun according to an embodiment of the invention;

FIG. 2 is a schematic block diagram of a compressed gas gun, in particular depicting the general pneumatic routing, according to embodiments of the invention;

FIG. 3a is a cross sectional side view of a compressed gas gun according to an embodiment of the invention, whereby the illustrated configuration shall be referred to as “in battery” in that it is ready to fire;

FIG. 3b is a close up cross sectional side view of a pneumatic assembly of the compressed gas gun of FIG. 3a;

FIG. 4 is a close up cross-sectional side view of a trigger assembly of the compressed gas gun of FIG. 3a;

FIG. 5a is a close up cross-sectional side view of a pneumatic assembly of the compressed gas gun of FIG. 3a showing a valve transitioning from closed state to an open state with on sealing surface opening and a larger sealing surface closing of the compressed gas gun of FIG. 3a;

FIG. 5b is a view similar to FIG. 5a showing the valve opened, allowing gas to flow into the gun's pneumatics;

FIG. 6a is a close up cross-sectional side view of a pneumatic assembly of the compressed gas gun of FIG. 3a showing the bolt closing and the first pellet being loaded;

FIG. 6b is a view similar to FIG. 6a showing gas flowing through the closed bolt, and into the breech;

FIG. 6c is a perspective view of a bolt of the trigger assembly of the compressed gas gun according to an embodiment of the invention;

FIG. 7a is a side view of a breech loaded with pellets and open passages to allow gas to flow around breeched pellets;

FIG. 7b is a cross sectional view through line E-E of FIG. 7a loaded with pellets and open passages to allow gas to flow around breeched pellets;

FIG. 8a is a longitudinal cross-sectional view of the breech of FIG. 7a loaded with pellets;

FIGS. 8b and 8c are cross-sectional views through line F-F of FIG. 8a, showing a detent spring in an unflexed position (FIG. 8a) and with the detent spring flexing to allow a pellet to pass into the barrel bore (FIG. 8b);

FIG. 9a is a perspective view of a barrel mount and detent spring with a pellet staged against the detent spring;

FIG. 9b is a longitudinal cross sectional view of the breech of FIG. 7a loaded with pellets;

FIG. 9c is a cross-sectional view through line G-G of FIG. 9b showing a breech face and the detent spring retaining a pellet before it enters into the barrel bore;

FIG. 10 is a perspective longitudinal cross-sectional view of a barrel and breech assembly loaded with pellets according to an embodiment of the invention;

FIGS. 11a to 11c are longitudinal cross-sectional views of a barrel and breech assembly of a compressed gas gun according to an embodiment of the invention. FIG. 11a showing a first pellet being fired. FIG. 11b showing a first pellet clearing a shoulder in the barrel allowing gas pressure to escape behind the pellet, and FIG. 11c showing the barrel and breech assembly cleared of pellets with gas flowing freely;

FIGS. 12a to 12e are close up cross-sectional side views of a pneumatic assembly of the compressed gas gun according to an embodiment of the invention, showing a pneumatic excess flow detecting assembly immediately before it changes state (FIG. 12a), the pneumatic excess flow detecting assembly after it has changed state to a closed state (FIG. 12b) and the pneumatic assembly reloading pellets (FIGS. 12c, 12d, and 12e);

FIGS. 13a and 13b are close up cross-sectional side views of the pneumatic assembly and trigger assembly with the trigger being released (FIG. 13a) and in a state with the trigger fully released (FIG. 13b);

FIG. 14a is a side view of a compressed gas gun according to an embodiment of the invention;

FIG. 14b is a cross-sectional view through line G-G of FIG. 14a showing a screw clamping and coaxial alignment scheme;

FIG. 15 is a side view of a compressed gas gun according to an embodiment of the invention;

FIGS. 15a to 15c are cross-sectional views through line J-J of FIG. 15 showing a magazine retention assembly receiving a magazine (FIG. 15a), the magazine retention assembly with magazine received (FIG. 15b), and with the magazine being removed (FIG. 15b).

FIGS. 16a and 16b are cross-sectional views of a barrel and nozzle of the compressed gas gun according to an embodiment of the invention. showing the dispersion of fired pellets increased (FIG. 16a), and pellets not affected by the nozzle (FIG. 16b);

FIG. 16c depicts a pattern of fired pellets discharged from the nozzle;

FIG. 16d is a frontal view of the nozzle assembly according to an embodiment designed to discharge an obround dispersion of fired pellets;

FIG. 16e is a perspective longitudinal cross-sectional view of a nozzle assembly which discharges an obround dispersion of fired pellets according to an embodiment of the invention;

FIG. 16f depicts an example of a dispersion of pellets from the embodiments of FIGS. 16d and 16e that is wider than it is tall.

DETAILED DESCRIPTION OF EMBODIMENTS

Referring to the figures, starting with FIG. 1, a compressed gas gun comprises a chassis 1, a pellet firing assembly 6 mounted in the chassis, a valve assembly 4 mounted in the chassis, a barrel assembly 7 partially mounted in the chassis, a grip 15 for holding the gun, a trigger assembly 3 comprising a trigger 30, and a magazine receiver 14 for holding a removable spring loaded magazine 50a for storing pellets 50.

The chassis 1 may advantageously have a generally prismatic shape. In a preferred embodiment the chassis may be made of a machined extruded aluminum part. The barrel assembly 7, grip 15, trigger 30, and magazine receiver 14 are attached to the chassis.

The compressed gas gun further comprises a refillable propellant gas storage reservoir 11 within the chassis 1 for storing a propellant gas, preferably partially compressed to a liquid state, refillable through a propellant fill valve 110 mounted on a wall of the chassis bounding the propellant gas storage reservoir 11 accessible by an operator. In an advantageous embodiment, the propellant fill valve is conveniently positioned on a top wall of the chassis for easy access by an operator to fill the propellant gas storage reservoir 11.

The propellant gas may for instance be butane or propane. Other compressed gases may be used as a propellant, such as nitrogen, argon, carbon dioxide, or air. Mixtures of the aforementioned gases may also be used as a propellant gas.

The compressed gas gun further comprises an expansion chamber 13 formed within the chassis, connected to the gas storage reservoir 11 via an adjustable pressure regulator 12 for storing expanded gas supplied from the gas storage reservoir 11 at a stable pressure.

In variants, an external gas supply instead of, or in addition to the gas storage reservoir 11 in the chassis 1, may be fed directly into the propellant gas storage reservoir 11, or directly into the expansion chamber 13, or in the pneumatic path upstream of the valve assembly 4.

The external gas supply may include a bulk storage bottle containing a compressed CO2 or HPA (high pressure air) system worn on a belt or backpack and connected to the compressed gas gun with a hose to convey gas to the gun. In embodiments, the external gas supply may include a pressure regulation system and be connected directly to the expansion chamber to feed gas into the expansion chamber 13. Alternatively, the external gas supply may be connected to the expansion chamber via the pressure regulator 12 mounted in the chassis 1.

In a variant, a propellant gas may be supplied by a compressed gas cylinder removably mounted within or on the chassis. In an embodiment, the compressed gas cylinder may be a disposable gas cylinder for instance with an opening that is pierced when it is mounted into the gun, said gas cylinder connected to the pressure regulator 12 mounted in the chassis and supplying gas into the expansion chamber 13.

The valve assembly 4 may be actuated by pulling the trigger 30 to admit propellant gas through a flow valve core 45 into the pellet firing assembly 6 of the compressed gas gun.

The propellant gas storage reservoir 11 is thermally well connected to the major body of the compressed gas gun formed by the chassis 1 which in turn is surrounded by the air in the environment, thus allowing the propellant gas storage reservoir to effectively absorb heat from the environment.

Pellets 50 loaded from a removable spring loaded magazine 50a feed upwards into the pellet firing assembly 6.

When the trigger is pulled, a component in trigger assembly 3 actuates a valve assembly 4 which releases compressed propellant gas into the pellet loading assembly 6 which accelerates pellets from the magazine 50a through the barrel assembly 7.

Referring to FIG. 3a, the compressed gas gun is depicted in an in battery, ready to fire, condition. The region enclosed in the upper portion of the prismatic chassis 1, preferably made of extruded and machined aluminum, contains a space used as a storage chamber which forms the propellant gas storage reservoir 11 for storing compressed gas and liquid. The propellant fill valve 110 is provided for refilling the gas storage reservoir 11 with a propellant gas by the operator. The pressure regulator assembly 12 is interposed between the gas storage reservoir 11 and another region in the prismatic chassis 1 which provides a space used as an propellant gas expansion chamber 13 which contains a stable pressure supply to provide pneumatic power to the pneumatic valve assembly 4 which is actuated by the trigger assembly 3.

A pellet loading assembly 6 receives compressed gas from valve assembly 4 which loads and applies pressurized gas to spherical pellets to load and accelerate them through barrel assembly 7.

Referring to FIG. 3b, the compressed gas gun in a condition that is in battery, a ready to fire condition. The bolt 62 is biased rearwards by a bolt return spring 629 which holds open a breech passage 630 in the breech from the magazine from which spherical pellets 50 are loaded. The magazine contains a spring 51 which urges pellets upwards out of the magazine and into a breech passage 630 in the breech 63.

As pellets enter the breech passage 630 and enter into the breech, a bolt nose 620 on the forward end of the bolt 62 has an inclined bolt nose tip 624 which faces slightly downwardly to deflect pellets coming up from the magazine forward into the breech 63. Pellets continue to advance forwards into the breech into a breech chamber 631 until the first pellet is stopped at a detent spring 67, which in an advantageous embodiment comprises or consists of a spring metal U-shaped wireform, which prevents the first pellet from exiting the breech.

Referring to FIG. 3c, pellets 50 and detent spring 67 are not sectioned in this view. Pellets loading into breech 63 feed forwards and compress into a triangular arrangement conforming to the shape of the cavity of breech 63, until they are stopped by the detent spring 67 positioned at the mouth of barrel mount 70.

Referring to FIG. 4, pulling the trigger 30 results in a trigger linkage arm 31 to be pulled forwards which in turn pulls a trigger lever 32 forwards urging the valve spool 40 towards its open state.

Referring to FIG. 5a, first and second seals 402 and 403, for instance in the form of O-rings, seal against first and second sealing bores with equal diameters in valve body 41 such that inlet gas pressure coming from propellant gas expansion chamber 13 acts with equal force on the flanges of valve spool 40.

As the valve spool 40 further travels forward, a third seal 404 engages a third sealing bore 404a that is larger than the first sealing bore 402a that first seal 402 is sealed upon. The forward face of the larger forward third sealing bore being connected to atmospheric pressure via a passage 401 through the center of the valve spool 40.

Referring to FIG. 5b, the valve spool has fully compressed it's return spring 405 and is fully open allowing gas to flow into the compressed gas gun's pneumatics. The difference in area between the larger third sealing bore 404a and smaller sealing first sealing bore 402a results in a net forward force exerted by static gas pressure between these sealing diameters.

A small difference in diameters between, larger third sealing bore 404a, and smaller first sealing bore 402a, are carefully chosen to result in a net force acting on valve spool 40 when it is pressed into it's fully open state which partially opposes the biasing force exerted by return spring 405 which provides a tactile trigger response which decreases the force required to actuate the valve spool 40 via the trigger assembly.

When the valve spool moves from its closed state (i.e. with first and second seals 402 and 403 engaged) to its open state (i.e. with first and third seals 402 and 404 engaged) a sharp decrease in the force required to depress valve spool 40 and compress spring 405 occurs. The abrupt change in force required to further compress spring 405 results in a tactile response when the user pulls the trigger which is desirable because it is an ergonomic way to indicate to the user when they have changed the state of the valve assembly.

In the opposite direction, trigger being released, valve spool 40 moves to its closed state, resulting in an abrupt increase in force applied to the trigger.

Referring to FIG. 5b, gas 420 flowing through the valve assembly flows through the ports 451 of an excess flow valve core 45 and out a central passage 452. A valve core return spring 454 biases the excess flow valve core 45 towards it's open state.

Referring to FIG. 6a, as gas rapidly flows out of the excess flow valve core 45 it passes through side port openings 480 cut out of a fixed piston 48 of the valve assembly 40. A piston probe 482 extending from a front end of the fixed piston 48 obstructs a central passage 622 of the bolt 62 when the bolt is in a rearward position. A fourth seal 481 on a main body portion of the fixed piston 48 traps gas exiting from the piston side port openings 480 in the rear bolt chamber 621 of the bolt 62 causing a rapid rise in pressure within the rear bolt chamber 621.

The bolt central passage 622 being smaller than the diameter of the rear bolt chamber 621 results in a net forward force when gas pressure acts upon the interior of the rear bolt chamber which urges the bolt 62 forwards compressing bolt return spring 629.

As the bolt 62 moves forwards, the inclined bolt nose 620 shears across the breech passage 630 which blocks the passage and prevents further feeding of pellets 50.

When bolt 62 pushes fully forward against breech 63, bolt passage 622 slides off of piston probe 482 which unblocks the bolt passage 622.

Referring to FIG. 6b, compressed gas is allowed to flow through bolt passage 622 and exit through a bolt nose outlet 623 extending through the nose of bolt (see FIG. 6c).

Referring to FIG. 6c, notches 625 cut into the flange of the bolt 62 provide alignment features to orient the bolt such that the inclined bolt nose tip 624 does not rotate.

Referring to FIGS. 7a and 7b, considerable area in the obround cross section of the breech exists around the pellets stored in the breech chamber 631. Gas introduced into the breech 63 urges chambered pellets forward, but much of gas is able to flow around the pellets through inter-pellet spaces in the breech chamber 633.

Referring to FIGS. 8a and 8b, when gas pressure flows around the chambered pellets and the staged pellet 501, the dominant restriction to gas flow becomes the staged pellet which imposes force upon the staged pellet 501 until it overcomes the detenting force provided by the detent spring 67.

Referring to FIG. 8c, as gas flow exerts more force, the staged pellet 501 deflects detent spring 67, and passes through it.

Referring to FIGS. 9a to 9c, the total area that is provided 632a around the forward most pellet 501, hereafter referred to as the staged pellet, is less free flowing than the spaces 633a between and around the pellets in the breech chamber 633 depicted in FIGS. 7a and 7b.

FIG. 10 is provided as a sectioned perspective view as an auxiliary view for clarity. Pellets 50 and detent spring 67 have not been sectioned to show their form.

Referring to FIG. 1la, under gas flow, the staged pellet 501 passes through the flexible detent spring 67 and into the barrel mount 70 which has a closely sized circular barrel introduction hole 701 sized to be slightly larger than the pellet. When the pellet has entered into the barrel mount 70 gas flow around the pellet 501 substantially ceases and the pellet is accelerated down the barrel. With inlet gas pressure acting to accelerate the pellet, pressure increases behind the accelerating pellet which reduces the flow rate of gas around the next pellet 501b to be staged against detent spring 67 and around chambered pellets in breech chamber 631.

Referring to FIG. 11b, when pellet 501 passes a widening shoulder 710 in the barrel 71 gas pressure in the barrel and barrel mount 70 can pass around the pellet 501 in this enlarged clearance around the pellet. Pressure behind the pellet in upstream barrel region 705 drops rapidly which increases the pressure drop over the next staged pellet held by detent spring 67 which in turn passes through detent spring 67 into barrel mount 70. This process is repeated until pellets preloaded into breech chamber 631 are exhausted.

Referring to Fig. 11c, when all pellets have been fired from the breech chamber 631, staging area 632, barrel mount 70, and barrel 71 are unrestricted which allows for a high rate of gas flow.

Referring to FIG. 12a, the high flow rate allowed by the now empty pellet loading assembly 6 and empty barrel assembly 7 imposes a sharp increase in pressure drop over excess flow valve core 45. The high pressure drop over excess flow valve core 45 overcomes the biasing force from valve core return spring 454.

At high gas flow rates, the excess flow valve core 45 is pushed forwards until a fifth seal 455 pushes into a fifth seal seat 483 thereby stopping the flow of gas out of valve assembly 4.

Referring to FIG. 12b, with gas flow stopped, the rear chamber of bolt 62 depressurizes and the bolt retracts rearwards, urged by the bolt return spring 629. The inclined bolt nose tip 624 retracts rearwards opening breech passage 630. Pellets feeding up from the magazine are not shown in this image.

Referring to FIGS. 12c, 12d, and 12e, once bolt 62 retracts fully rearward and pellets 50 have been reloaded into breech chamber 633 the pellet reloading assembly has been reset and reloaded to be ready to fire for the next time the valve assembly is triggered.

Referring to FIG. 13a, releasing the trigger 30 moves the trigger linkage 31 and allows trigger lever 32 to pivot rearwards, which in turn allows spring 405 to return valve spool 40 to it's closed position stopping the flow of gas out of the propellant gas expansion chamber 13.

Referring to FIG. 13b, when the trigger 30 has been fully released, valve spool 40 returns to it's rearward position, third seal 404 slides out of it's cylinder seat allowing gas to flow rearwards out of the valve core chamber 456 behind the excess flow valve 45 and escape to atmosphere through spool passage 401. The release of third seal 404 from the third sealing bore 404a results in a sharp increase in force exerted by the spool valve rearwards when return spring 405 is no longer partially opposed by the static pressure acting on the difference in area of the third and first sealing bores 404a and 402a. This results in a tactile bump in the trigger felt by the user which provides a notification of the valve having been reset.

When valve core chamber 456 depressurizes the static pressure acting to hold flow valve core 45 forwards dissipates and valve core return spring 454 pushes flow valve core 45 into it's open state.

Referring to FIGS. 14a and 14b, a prismatic profile of the chassis 1 provides two angled guide surfaces 101 which provide convenient coaxial alignment features for multiple cylindrical components such as valve assembly 4, breech 63, and barrel mount 70 which all require good coaxial alignment. Clamp screws 102 are threaded into the opposite side of chassis 1 where they are needed to clamp cylindrical components against angled guide surfaces 101.

Referring to FIGS. 15. 15a, 15b, and 15c, a sprung magazine retention element 16 provides retention of the magazine 50a through engagement of the magazine retention window 50a1. The retention feature could be provided by a rigid hinged biased element, or preferably a flexible sheet metal element that provides two sloped faces 161 and 162 to actuate the magazine retention element 16 with the insertion or removal of the magazine 50a.

Referring to FIG. 15a, when the user inserts the magazine 50a the upper edge of the magazine 50a2 engages the lower slope face 161 of the magazine retention element 16 to flex the magazine retention element 16 outwards to allow passage of the magazine into the receiver.

In the received position. FIG. 15b, the magazine retention element 16 biases into the retention window of the magazine such that the upper slope of the spring retention element 162 rests against the upper edge of the retention window 50a1.

Referring to FIG. 15c, when the magazine 50a is being removed, the angle of the upper slope 162 on magazine retention element 16 results in a lateral force which flexes the retention element outwards allowing the removal of the magazine.

Referring to FIGS. 16a to 16e, the compressed gas gun according to an embodiment of the invention comprises a pellet dispersing device comprising a pellet dispersing nozzle 80 mounted on the end of the barrel 71, and an enlargened bore section 712 forming a widening shoulder 710 in the barrel 71 proximal the end of the barrel. The pellet enlargened bore section 712 in conjunction with the dispersing nozzle 80 alters the pattern of the distribution of pellets fired from the barrel.

When fired pellets clear the widening shoulder 710 in the barrel 71 they will begin to deviate from a straight path aligned with the center axis 711 of the barrel. Along the length of the enlargened bore section 712 from the widening shoulder 710 the pellets randomly deviate from a straight path collinear from the central axis of the barrel before they enter in the dispersing nozzle 80 and may impinge upon a gentle constricting taper 800 inside of nozzle 80 which tends to further deflect the path of an individual pellet such that it achieves a significantly broader spread than would be accomplished without a deflection after the pellet clears the widening shoulder, or exits a barrel with a constant diameter without a shoulder. The taper has a gently reducing diameter or cross-sectional surface area in the direction of projectile displacement to deflect pellets deviating from the barrel bore centreline exiting the enlargened bore section 712. The spread provided by the angle of the constricting taper 800 could be changed to provide a nozzle of a different degree of spread. In an embodiment, the constricting taper may have an axisymmetric shape. Other shapes that constrict towards the outlet of the nozzle could also be used.

Generally speaking the natural dispersion of pellets as they depart from the end of a barrel, or barrel shoulder will be smaller than the intentional taper angle machined into the nozzle taper 800.

Referring to FIG. 16b, some pellets which do not diverge significantly from the center axis of the barrel will pass through the outlet hole of taper 800 undiverted.

Referring to FIG. 16c, the dispersion of pellets tends to form a ring pattern surrounding a central group which is useful for increasing hit probability on one or more targets at close range while still maintaining a compact shot pattern density in the central group for striking targets at longer range.

Referring to FIG. 16d, according to a variant, the pellet dispersion nozzle 80 comprises a constricting taper and outlet of the tape which is configured to provide an obround dispersion of pellets. For this, either the constricting taper has a non-axisymmetric shape (e.g. a generally oval cross-section profile), or the outlet 810 has a non-axisymmetric shape, or both the outlet 810 and the taper 800 have non-axisymmetric shapes. In the illustrated embodiment, the outlet 810 of the non-axisymmetric constricting taper 800 is in the form of an obround opening. The obround outlet 810 may for instance have a height 811 similar to the outlet diameter 820 of the barrel and a width greater than the diameter 820. The obround outlet 810 may for instance be provided on an insert 81 pressed axially into the body of the nozzle 80 from the large open end of the nozzle.

Referring to FIG. 16e, the obround taper 800 or outlet 810 confines the vertical deflection of pellets emerging from the nozzle 80 resulting in an obround dispersion of pellets illustrated in FIG. 16f.

The nozzle 80 can be mounted in different rotational positions, in particular horizontal and vertical positions so that the user may select from a horizontally dispersed obround pattern, useful for striking multiple targets arrayed in the horizontal axis, or a vertically dispersed obround pattern useful for striking a target that is taller than it is wide.

Advantages of Embodiments of the Invention

The compressed gas gun of embodiments of the invention has many improvements over the prior art including: an integrated design which can carry onboard a useful quantity of propellant and pellets, which does not require the use of an external pressure source; an integrated thermal design which can rapidly provide heat to the onboard pressure source, preferably a two-phase liquid gas propellant; an internal pressure regulator which can stabilize operating pressure despite changes in operating temperature of the gun; an internal breech arrangement which can rapidly, individually, accelerate pellets at a high rate of fire giving the impression of a shotgun like blast.

A breech chamber located at the rear end of the barrel may be configured to fire multiple pellets in either one group with multiple pellets being accelerated through the barrel at one time, or the breech may be configured to load and fire pellets in rapid succession with only one pellet being accelerated at a time down the barrel in a short burst of pellets fired at very high frequency typically in the 100 rounds per second or higher. This rate of fire tends to be so high that the firing of a load of 10 pellets appears to be fired as a single burst rather than a fully automatic sequence of pellets.

An arrangement of a storage reservoir, preferably for storing a two-phase compressed gas-liquid charge, that has a highly heat conductive connection to much of the total surface area of the gun via conductive materials such as aluminum. Preferably the storage reservoir is integrated into a continuous extrusion which forms the main chassis of the gun which provides a large surface area to provide heat absorption via convection heat transfer to the environment and a high heat capacity in the mass of the chassis and attached components which may also be thermally junctioned to the chassis to provide further heat capacity and improve access to surface area for heat absorption from the environment.

Typically the use of a two-phase compressed gas supply requires considerable input of heat as the gun is fired multiple times to provide heat to evaporate the liquid phase of the propellant charge. It is advantageous to have a large heat sink to provide heat capacity and increased surface area to provide heat to the liquid phase of the propellant charge to provide heat for sustained fire.

A two-phase (liquid. gas) pressure supply is a convenient means to provide compact pressure supply without requiring the very high pressures typical of an single phase ideal gas supply.

A pressure regulator supplying gas to a second stage lower pressure gas reservoir to supply the firing pneumatics of the gun. Both of these chambers being integral to the main chassis of the gun to supply a high amount of heat capacity on the material of the chassis and well thermally connected surface area to absorb heat from the environment.

While it is preferable to supply the gun from an integrated two-phase pressure supply, an external gas supply, either unregulated two-phase, regulated two-phase, or regulated single phase pressure source, could be connected to the gun to supply pressure to provide a large volume of propellant for long periods of sustained fire or otherwise improved fire capability.

An arrangement of valves supplies propellant to the pneumatic action of the gun and also provides a tactile force feedback to the trigger so the user may feel a tactile “break” in the trigger when it is pulled to actuate the gun and a tactile sense to feel when the pneumatics have reset as the trigger is released. Previous implementations of pneumatic trigger valves have usually required more complex mechanisms to provide a tactile sense of a trigger break or they would have a indeterminate tactile trigger response which is less desirable.

Pellets are received from a removable spring loaded magazine which feeds pellets into a breech which may hold one or more, typically 10 pellets, which are rapidly introduced into the barrel and accelerated with gas pressure. The breech can be easily configured for accelerating multiple pellets simultaneously to achieve lower muzzle velocity, or configured

to accelerate pellets one at a time through the barrel in very rapid succession to achieve higher muzzle velocity.

The removable magazine is retained with a sheet metal spring which biases a form into a rectangular hole cut into the side of the magazine such that the user does not need to actuate a mechanism with a separate motion in order to remove the magazine. Extraction of the magazine can be accomplished with a deliberate downwards pull on the magazine. The sheet metal retention spring is adjustable in placement via a screw in a slotted mounting hole and tension adjustable through the addition of accessory leaf springs.

The shape of the front of the breech dimensioned and provided with a detent feature to hold pellets at the barrel entry until the previous pellet has been accelerated and discharged at which point the next pellet is admitted into the barrel to provide a means to provide high muzzle velocity at relatively low breech pressure commanded by a single trigger pull to discharge a complete burst.

A second sprung detent feature placed partially down the barrel, instead of at the barrel's entry, provides a stronger backspin to each pellet allowing the use of more durable, lower friction materials in this backspin feature, while providing a strong backspin effect to create lift via the Magnus effect for lifting heavier pellets.

A nozzle shaped to provide an intentional spread of pellets that may be round or non round to improve hit probability.

In summary, advantages of the invention include

• • the ability to fire multiple pellets per trigger pull, fed by spherical pellets from an economical convenient magazine;
  • an integrated gas storage system with high thermal transfer;
  • an efficient design requiring a minimum of components;
  • a convenient way to align critical components to ease assembly and maintenance;
  • a means to adjust the fired pattern of pellets;
  • a novel valve design to provide a tactile trigger reset effect; and
  • a novel magazine retention system that is both easy to use while reducing the number of necessary components.

List of Features

• • chassis 1
  • extruded aluminum chassis
  • angled guide surfaces 101
  • propellant gas storage reservoir 11
  • propellant fill valve 110
  • magazine receiver 14
  • adjustable pressure regulator 12
  • propellant gas expansion chamber 13
  • grip 15
  • magazine retention element 16
  • sloped faces 161 and 162
  • clamp screws 102
  • trigger assembly 3.
  • trigger 30
  • trigger linkage arm 31
  • trigger lever 32
  • valve assembly 4
  • valve spool 40
  • spool passage 401
  • first seal 402
    • O-ring
  • second seal 403
  • O-ring
  • third seal 404
  • return spring 405
  • first sealing bore 402a
  • third sealing bore 404a
  • valve body 41
  • gas 420
  • flow valve core 45
  • ports 451
  • central passage 452
  • valve core return spring 454
  • fifth seal 455
  • valve core chamber 456
  • fixed piston 48
  • side port openings 480
  • fourth seal 481
  • piston probe 482
  • fifth seal seat 483
  • Pellets 50
  • spherical pellets
  • staged pellet 501
  • next pellet 501b
  • magazine 50a
  • magazine retention window 50a1
  • upper edge of the magazine 50a2
  • magazine spring 51
  • pellet loading assembly 6
  • bolt 62
  • rear bolt chamber 621
  • bolt passage 622
  • bolt nose outlet 623
  • bolt nose 620
  • inclined bolt nose tip 624
  • notches 625
  • bolt return spring 629
  • breech 63
  • cavity of breech 63
  • breech passage 630
  • breech chamber 631
  • total area that is provided 632a
  • staging area 632
  • breech chamber 633
  • inter-pellet spaces 633a
  • detent spring 67
  • wireform
  • barrel assembly 7
  • mouth of barrel mount 70
  • upstream barrel region 705
  • circular barrel introduction hole 701
  • barrel 71
  • widening shoulder 710
  • center axis of the barrel 711
  • enlargened bore section 712
  • pellet dispersing nozzle 80
  • constricting taper 800
  • insert 81
  • obround outlet 810
  • height 811
  • outlet diameter 820

Claims

1.-58. (canceled)

59. A compressed gas gun comprising a chassis, a pellet firing assembly including a breech and a slidable bolt mounted in the chassis, a valve assembly mounted in the chassis, a barrel assembly comprising a barrel, a grip for holding the gun, a trigger assembly comprising a trigger, and a magazine receiver for holding a removable magazine for storing pellets, wherein the compressed gas gun further comprises: a refillable propellant gas storage reservoir formed within the chassis, andan expansion chamber formed within the chassis, connected to the gas storage reservoir via a pressure regulator for storing expanded gas supplied from the gas storage reservoir, the expansion chamber supplying propellant gas to the pellet firing assembly via the valve assembly.

60. The compressed gas gun of claim 59, wherein the propellant gas storage reservoir and the expansion chamber are bounded by walls of the chassis, the propellant gas storage reservoir refillable through a propellant fill valve accessible by an operator.

61. The compressed gas gun of claim 60, wherein the propellant fill valve is positioned on and extends through one of said walls of the chassis, preferably a top wall of the chassis.

62. The compressed gas gun of claim 59, wherein the pressure regulator is adjustable.

63. The compressed gas gun of claim 59, wherein the chassis has a generally prismatic shape made of a machined extruded part.

64. The compressed gas gun of claim 63, wherein the chassis is made of an extruded machined aluminium part.

65. The compressed gas gun of claim 59, wherein the barrel assembly, grip, trigger, and magazine receiver are assembled and fixed to the chassis.

66. The compressed gas gun of claim 59, wherein the slidable bolt comprises a bolt nose, a central bolt passage extending through the bolt nose, and a rear bolt chamber fluidly connected to the central bolt passage, the bolt nose comprising bolt nose outlets fluidly connected to the central bolt passage for the passage of propellant gas from a rear end of the bolt through the rear bolt chamber to a breech chamber of the breech.

67. The compressed gas gun of claim 66, wherein the bolt nose comprises an inclined bolt nose tip facing slightly downwardly and forwardly configured to push pellets from the magazine to the breech chamber.

68. The compressed gas gun according to claim 66, wherein the valve assembly comprises a fixed piston comprising a piston probe sealingly insertable in the central bolt passage configured to seal the central passage to block the flow of propellant gas to the breech chamber when the bolt is in a rearward position, and the piston probe configured to disengage the bolt passage when the bolt is in a forward position allowing propellant gas to flow through to the breech chamber.

69. The compressed gas gun according to claim 59, further comprising a pellet dispersing device comprising a pellet dispersing nozzle mounted on an end of the barrel, and an enlargened bore section forming a widening shoulder in the barrel proximal the end of the barrel, the pellet dispersing nozzle comprising a constricting tapered bore (800) configured to deflect pellets to increase their dispersion.

70. The compressed gas gun according to claim 69, wherein the constricting tapered bore has a non-axisymmetric shape, or an outlet of the constricting tapered bore has a non-axisymmetric shape, or both the constricting tapered bore and the outlet have a non-axisymmetric shape configured to disperse pellets in an obround area.

71. The compressed gas gun according to claim 59, wherein the breech comprises a breech chamber configured to receive a plurality of pellets therein forming spaces therearound for flow of propellant gas towards the barrel bore, an end of the breech chamber interfacing with the barrel bore comprising a detent spring retaining the pellet in the breech chamber with a predefined spring force.

72. The compressed gas gun according to claim 71, wherein the detent spring comprises or consists of a generally U-shaped spring wireform.

73. The compressed gas gun according to claim 59, wherein the valve assembly comprises a slidable valve spool engageable by a trigger linkage coupled to the trigger, the valve spool having a first seal engaging in a fixed first sealing bore on a rear end and a second seal engaging a fixed second sealing bore on a forward end, the first and second seals having the same diameter, wherein the valve spool further comprises a third seal downstream of the second seal and having a slightly larger diameter than the first and second seal, the third seal configured to engage a third sealing bore when the second seal disengages the second sealing bore configured to provide tactile feedback on the trigger of a firing action.

74. A compressed gas gun comprising a chassis, a pellet firing assembly including a breech and a slidable bolt mounted in the chassis, a valve assembly mounted in the chassis, a barrel assembly comprising a barrel, a grip for holding the gun, a trigger assembly comprising a trigger, and a magazine receiver for holding a removable magazine for storing pellets, wherein the slidable bolt comprises a bolt nose, a central bolt passage extending through the bolt nose, and a rear bolt chamber fluidly connected to the central bolt passage, the bolt nose comprising bolt nose outlets fluidly connected to the central bolt passage for the passage of propellant gas from a rear end of the bolt through the rear bolt chamber to a breech chamber of the breech.

75. The compressed gas gun of claim 74, wherein the bolt nose comprises an inclined bolt nose tip facing slightly downwardly and forwardly configured to push pellets from the magazine to the breech chamber.

76. The compressed gas gun according to claim 74, wherein the valve assembly comprises a fixed piston comprising a piston probe sealingly insertable in the central bolt passage configured to seal the central passage to block the flow of propellant gas to the breech chamber when the bolt is in a rearward position, and the piston probe configured to disengage the bolt passage when the bolt is in a forward position allowing propellant gas to flow through to the breech chamber.

77. The compressed gas gun of claim 74, wherein the chassis has a generally prismatic shape made of a machined extruded part.

78. The compressed gas gun of claim 77, wherein the chassis is made of an extruded machined aluminium part.

79. The compressed gas gun of claim 74, wherein the barrel assembly, grip, trigger, and magazine receiver are assembled and fixed to the chassis.

80. The compressed gas gun according to claim 74, further comprising a pellet dispersing device comprising a pellet dispersing nozzle mounted on an end of the barrel, and an enlargened bore section forming a widening shoulder in the barrel proximal the end of the barrel, the pellet dispersing nozzle comprising a constricting tapered bore (800) configured to deflect pellets to increase their dispersion.

81. The compressed gas gun according to claim 80, wherein the tapered bore has a non-axisymmetric shape, or an outlet of the tapered bore has a non-axisymmetric shape, or both the tapered bore and the outlet have a non-axisymmetric shape configured to disperse pellets in an obround area.

82. The compressed gas gun according to claim 74, wherein the breech comprises a breech chamber configured to receive a plurality of pellets therein forming spaces therearound for flow of propellant gas towards the barrel bore, an end of the breech chamber interfacing with the barrel bore comprising a detent spring retaining the pellet in the breech chamber with a predefined spring force.

84. The compressed gas gun according to claim 82, wherein the detent spring comprises or consists of a generally U-shaped spring wireform.

85. The compressed gas gun according to claim 74, wherein the valve assembly comprises a slidable valve spool engageable by a trigger linkage, the valve spool having a first seal engaging in a fixed first sealing bore on a rear end and a second seal engaging a fixed second sealing bore on a forward end, the first and second seals having the same diameter, wherein the valve spool further comprises a third seal downstream of the second seal and having a slightly larger diameter than the first and second seal, the third seal configured to engage a third sealing bore when the second seal disengages the second sealing bore configured to provide tactile feedback on the trigger of a firing action.

86. A compressed gas gun comprising a chassis, a pellet firing assembly including a breech and a slidable bolt mounted in the chassis, a valve assembly mounted in the chassis, a barrel assembly comprising a barrel, a grip for holding the gun, a trigger assembly comprising a trigger, and a magazine receiver for holding a removable magazine for storing pellets, wherein the valve assembly comprises a slidable valve spool engageable by a trigger linkage, the valve spool having a first seal engaging in a fixed first sealing bore on a rear end and a second seal engaging a fixed second sealing bore on a forward end, the first and second seals having the same diameter, wherein the valve spool further comprises a third seal downstream of the second seal and having a slightly larger diameter than the first and second seal, the third seal configured to engage a third sealing bore when the second seal disengages the second sealing bore configured to provide tactile feedback on the trigger of a firing action.

87. The compressed gas gun of claim 86, wherein the chassis has a generally prismatic shape made of a machined extruded part.

88. The compressed gas gun of claim 87, wherein the chassis is made of an extruded machined aluminium part.

89. The compressed gas gun of claim 86, wherein the barrel assembly, grip, trigger, and magazine receiver are assembled and fixed to the chassis.

90. The compressed gas gun of claim 86, wherein the slidable bolt comprises a bolt nose, a central bolt passage extending through the bolt nose, and a rear bolt chamber fluidly connected to the central bolt passage, the bolt nose comprising bolt nose outlets fluidly connected to the central bolt passage for the passage of propellant gas from a rear end of the bolt through the rear bolt chamber to a breech chamber of the breech.

91. The compressed gas gun of claim 90, wherein the bolt nose comprises an inclined bolt nose tip facing slightly downwardly and forwardly configured to push pellets from the magazine to the breech chamber.

92. The compressed gas gun according to claim 90, wherein the valve assembly comprises a fixed piston comprising a piston probe sealingly insertable in the central bolt passage configured to seal the central passage to block the flow of propellant gas to the breech chamber when the bolt is in a rearward position, and the piston probe configured to disengage the bolt passage when the bolt is in a forward position allowing propellant gas to flow through to the breech chamber.

93. The compressed gas gun according to claim 86, further comprising a pellet dispersing device comprising a pellet dispersing nozzle mounted on an end of the barrel, and an enlargened bore section forming a widening shoulder in the barrel proximal the end of the barrel, the pellet dispersing nozzle comprising a constricting tapered bore (800) configured to deflect pellets to increase their dispersion.

94. The compressed gas gun according to claim 93, wherein the tapered bore has a non-axisymmetric shape, or an outlet of the tapered bore has a non-axisymmetric shape, or both the tapered bore and the outlet have a non-axisymmetric shape configured to disperse pellets in an obround area.

95. The compressed gas gun according to claim 86, wherein the breech comprises a breech chamber configured to receive a plurality of pellets therein forming spaces therearound for flow of propellant gas towards the barrel bore, an end of the breech chamber interfacing with the barrel bore comprising a detent spring retaining the pellet in the breech chamber with a predefined spring force.

96. The compressed gas gun according to claim 95, wherein the detent spring comprises or consists of a generally U-shaped spring wireform.

97. A compressed gas gun comprising a chassis, a pellet firing assembly including a breech and a slidable bolt mounted in the chassis, a valve assembly mounted in the chassis, a barrel assembly comprising a barrel, a grip for holding the gun, a trigger assembly comprising a trigger, and a magazine receiver for holding a removable magazine for storing pellets, further comprising a pellet dispersing device comprising a pellet dispersing nozzle mounted on an end of the barrel, and an enlargened bore section forming a widening shoulder in the barrel proximal the end of the barrel, the pellet dispersing nozzle comprising a constricting tapered bore (800) configured to deflect pellets to increase their dispersion.

98. The compressed gas gun according to claim 97, wherein the constricting tapered bore has a non-axisymmetric shape, or an outlet of the constricting tapered bore has a non-axisymmetric shape, or both the constricting tapered bore and the outlet have a non-axisymmetric shape configured to disperse pellets in an obround area.

99. The compressed gas gun according to claim 97, wherein the breech comprises a breech chamber configured to receive a plurality of pellets therein forming spaces therearound for flow of propellant gas towards the barrel bore, an end of the breech chamber interfacing with the barrel bore comprising a detent spring retaining the pellet in the breech chamber with a predefined spring force.

100. The compressed gas gun according to claim 99, wherein the detent spring comprises or consists of a generally U-shaped spring wireform.

101. The compressed gas gun of claim 97, wherein the chassis has a generally prismatic shape made of a machined extruded part.

102. The compressed gas gun of claim 101, wherein the chassis is made of an extruded machined aluminium part.

103. The compressed gas gun of claim 97, wherein the barrel assembly, grip, trigger, and magazine receiver are assembled and fixed to the chassis.

104. The compressed gas gun of claim 97, wherein the slidable bolt comprises a bolt nose, a central bolt passage extending through the bolt nose, and a rear bolt chamber fluidly connected to the central bolt passage, the bolt nose comprising bolt nose outlets fluidly connected to the central bolt passage for the passage of propellant gas from a rear end of the bolt through the rear bolt chamber to a breech chamber of the breech.

105. The compressed gas gun of claim 104, wherein the bolt nose comprises an inclined bolt nose tip facing slightly downwardly and forwardly configured to push pellets from the magazine to the breech chamber.

106. The compressed gas gun according to claim 104, wherein the valve assembly comprises a fixed piston comprising a piston probe sealingly insertable in the central bolt passage configured to seal the central passage to block the flow of propellant gas to the breech chamber when the bolt is in a rearward position, and the piston probe configured to disengage the bolt passage when the bolt is in a forward position allowing propellant gas to flow through to the breech chamber.

107. The compressed gas gun according to claim 97, wherein the valve assembly comprises a slidable valve spool engageable by a trigger linkage, the valve spool having a first seal engaging in a fixed first sealing bore on a rear end and a second seal engaging a fixed second sealing bore on a forward end, the first and second seals having the same diameter, wherein the valve spool further comprises a third seal downstream of the second seal and having a slightly larger diameter than the first and second seal, the third seal configured to engage a third sealing bore when the second seal disengages the second sealing bore configured to provide tactile feedback on the trigger of a firing action.

108. The compressed gas gun of claim 97, further comprising: a refillable propellant gas storage reservoir formed within the chassis, andan expansion chamber formed within the chassis, connected to the gas storage reservoir via a pressure regulator for storing expanded gas supplied from the gas storage reservoir, the expansion chamber supplying propellant gas to the pellet firing assembly via the valve assembly.

109. The compressed gas gun of claim 108, wherein the propellant gas storage reservoir and the expansion chamber are bounded by walls of the chassis, the propellant gas storage reservoir refillable through a propellant fill valve accessible by an operator.

110. The compressed gas gun of claim 109, wherein the propellant fill valve is positioned on and extends through one of said walls of the chassis, preferably a top wall of the chassis.

111. The compressed gas gun of claim 108, wherein the pressure regulator is adjustable.

112. The compressed gas gun according to claim 97, comprising an external gas supply.

113. The compressed gas gun according to claim 112, wherein the external gas supply comprises a bulk storage bottle containing a compressed CO2 or HPA (high pressure air) system worn on a belt or backpack and connected to the compressed gas gun with a hose.

114. The compressed gas gun according to claim 112, wherein the external gas supply comprises a compressed gas cylinder removably mounted within or on the chassis

115. The compressed gas gun according to claim 112, wherein the compressed gas gun comprises an expansion chamber and the external gas supply is connected directly to the expansion chamber to feed gas into the expansion chamber.

116. The compressed gas gun according to claim 97, wherein the magazine receiver comprises a spring magazine retention element fixed to a side wall of the magazine receiver, the spring magazine retention element having a V shaped finger extending through an orifice in the side wall and configured to engage in a magazine retention window or notch in the side of the magazine.

117. The compressed gas gun according to claim 116, wherein the spring magazine retention element comprises or consists of a stamped and formed spring sheet metal.