Gun And Projectile For Shooting Fluids

Abstract

A gun and projectile for shooting a volume of fluid or gas payload such as water, napalm jelly, or a marker dye. The fluid is enclosed in a thin plastic envelope carried by a sabot which is mounted in a cartridge case for breech loading in the gun. The cartridge includes a self contained deflagration charge and primer which, when ignited by the firing mechanism of the gun, generates gas which fills an expansion chamber in the receiver of the gun. The gas pressure builds up within the chamber to a predetermined value at which a frangible connection between the sabot and cartridge base is broken allowing relatively low pressure gases to act against the sabot seal plate through a large port in the cartridge base and urge the sabot from the barrel and along its trajectory towards the target. In flight the sabot elements fall away allowing only the envelope of fluid to strike the target.

Description

BACKGROUND OF THE INVENTION

This invention relates to hand carried guns or firearms adapted to fire relatively fragile, large caliber projectiles. More particularly, the invention relates to firearms or guns for firing any fluid, gas, or combination fluid/gas in a large caliber projectile for uses in areas such as the military, anti-riot law enforcement, or forestry service.

Guns have previously been developed for firing relatively heavy, large caliber projectiles containing fragile payloads such as illuminating flares with or without parachutes, impact testing projectiles, harpoons, sonobuoys, and dart projectiles containing payloads such as explosives, tear gas, marker dyes, or hypodermic syringes. Certain of these guns are characterized in using expansion chambers to reduce the gas pressure for propelling the heavy projectile. Many of these guns require separate gas generating charges, such as a blank rifle or pistol cartridge, while the guns with charges integral with the projectile are muzzle loaded, such as in mortars.

Prior art devices for firing fluids, such as darts containing a marker dye, are characterized in that the dye fluid is released when the dart strikes the target, and this is oftentimes objectionable and hazardous in that the resulting impact from the dart is injurious where an individual is the target during riot control. Accordingly, the need has been recognized for a small and compact hand carrier breech loading gun which will propel a relatively large mass of fluid, gas or jelly toward a target at a relatively low velocity (160 ft./sec) and deliver a large amount of energy over a wide area so as to stop or knock down an assailant, but not fatally injure him.

SUMMARY AND OBJECTS OF THE INVENTION

It is an object of the invention to provide a projectile having a fluid, gas or jelly payload, and a device for firing the payload toward a target.

Another object is to provide a method for use in suppressing personnel without lethal injury by propelling a weight of fluid in a flexible envelope at a velocity to yield a given energy range upon impact.

Another object is to provide a breech loading gun of compact design which incorporates an expansion chamber for developing relatively low pressure gases to fire a fragile projectile having a fluid, gas or jelly payload.

Another object is to provide a gun and cartridge combination in which the gun has an expansion chamber and in which the cartridge is breech loaded and includes a self-contained deflagration charge which, when ignited, generates gas pressure within the expansion chamber for propelling the payload in the cartridge along a trajectory towards the target.

Another object is to provide a gun for firing a fragile payload of a fluid or jelly having a relatively large mass, in which gas pressure generated within an expansion chamber of the gun acts against a sabot containing the payload with the sabot elements falling free as the projectile leaves the muzzle permitting the payload to continue on its trajectory towards the target.

Another object is to provide a gun and cartridge combination for firing a fragile payload of a relatively large mass in which gas pressure builds up within an expansion chamber of the gun to a predetermined value sufficient to shear a break element joining the cartridge base and sabot whereby the latter is propelled from the gun.

Another object is to provide a projectile for firing a relatively large mass of liquid or jelly payload from a gun in which the liquid or jelly is sealed in a light-weight flexible envelope contained in a sabot having a plurality of releasably interfitting elements adapted to separate upon leaving the gun's muzzle permitting the payload to continue on its trajectory toward the target.

The foregoing and other objects and advantages of the invention are provided by the present invention in which a hand carried gun of relatively small and compact design fires a projectile containing a variety of payloads useful in riot control, military application, or forestry service, and the like.

The payload is fired in a sabot-type projectile from relatively low pressure gases developed in an expansion chamber of the gun. The projectile includes a self-contained deflagration charge developing the gas when fired by a firing mechanism in the gun. The projectile is breech loaded to facilitate handling and operating the gun, and to permit rapid re-loading. The projectile payload of fluid, such as water or jelly, is sealed in a lightweight, flexible envelope which in turn is contained in a sabot defined by a plurality of releasably interconnected, lightweight elements mounted in the cartridge case. The gas pressure developed in an expansion chamber of the gun acts against the sabot urging it from the muzzle where the sabot elements rapidly fall away permitting the envelope of fluid to proceed on its trajectory toward the target. A powder charge in the base of the cartridge generates the gas which enters the expansion chamber and builds up to a predetermined pressure effective to act against the face of the sabot shearing a break element normally holding the sabot with the cartridge base. This gas pressure moves the sabot along the barrel with the sabot elements protecting the fluid envelope until discharging from the muzzle. Dynamic air pressure acting through an opening in the forward end of the sabot separates the sabot elements which rapidly fall away from the payload. When the payload strikes the target, the envelope ruptures and the enclosed fluid or jelly bursts outwardly onto the target area.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational section view of a gun and cartridge incorporating features of the invention showing the cartridge loaded in the gun prior to firing;

FIG. 2 is an enlarged fragmentary view of the gun and cartridge of FIG. 1;

FIG. 3 is a view similar to FIG. 2 illustrating operation after firing of the gun;

FIG. 4 is a cross sectional view taken along the line 4--4 of FIG. 3;

FIG. 5 is an exploded, perspective view illustrating component elements of the cartridge of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In the drawings FIG. 1 illustrates generally at 10 my improved gun for firing a fluid or jelly-like payload toward a selected target. In the illustrated embodiment this payload includes a liquid such as water contained in cartridge 11 for use by law enforcement personnel or the like in quelling rioters or other disorderly individuals. It is understood that the invention has further application such as in propelling napalm jelly in military operations, or by the forestry service in propelling a treatment fluid to an inaccessible infected area of a tree.

Cartridge 11 is of large caliber adapted to contain a relatively large mass of the fluid or jelly payload. As illustrated in FIGS. 2, 4 and 5 this cartridge includes a cylindrical cartridge case 12 secured to annular cartridge base 13 for receiving a projectile or sabot 14 which in turn contains the payload of fluid or jelly 16 sealed within a lightweight bag or envelope 17.

Flexible bag or envelope 17 may be of any suitable fluid-impervious material adaptable for retaining the payload in the cartridge for storage, which has sufficient strength for holding the fluid as it moves along its trajectory towards the target, and which will burst under hydraulic pressure as the payload strikes a target. A suitable synthetic polymer such as polyethylene film plastic is satisfactory for enclosing a fluid such as water for use in anti-riot control. When thus used the envelope of water will easily burst upon impact without harming an individual, and yet the water will disperse in the target area for discouraging further rioting. The impact force of the water and plastic envelope will also tend to discourage rioting by temporarily shocking the individual.

The payload or projectile may be varied in weight and velocity so as to control the energy at impact. The heavy, slower projectile is relatively limited in range, but is less likely to injure. The lighter, faster projectile containing the same energy has a longer effective range, but generates higher dynamic pressures at impact and is more likely to injure. A preferred example would be a projectile of 10 oz. at 160 f.p.s. which will yield 250 ft. lbs. of energy and has a reasonably accurate range at 125 ft. This impact energy may be selectively varied depending upon the desired physical impact effect on the target personnel, with a risk of injury resulting at the higher energy levels. The invention contemplates a fluid weight range of 6-15 oz. propelled at a sufficient velocity to yield from 200-400 ft. lbs. of energy upon impact.

When used in anti-riot control the payload of water 16 may be combined with any suitable visible dye or marker fluid which disperses upon impact so that individuals contacted by the fluid are marked for subsequent identification purposes. As desired, a fluorescent dye visible under infrared light may also be combined in the payload for identifying the rioters.

The payload within envelope 17 may also include a suitable lachrymatory or nauseating gas, or combination of the two, under pressure and sealed by the envelope. Upon impact with the target the envelope would burst and release the gas for immobilizing the individuals or to otherwise discourage rioting.

For military applications the payload within envelope 17 would include a conventional napalm jelly together with a suitable lighter fuse, not shown, to ignite the napalm. This fuse could be of the impact type adapted to ignite upon impact with the target, or of the timer type adapted to ignite after a predetermined time following firing from the gun. In this application it is possible to deliver the napalm on target at a relatively long range and with improved accuracy as compared to flame thrower weapons, for example.

For use in the forestry applications envelope 17 would enclose a solution of anti-fungus fluid or the like which would be carried to an inaccessible infected area of a tree. The individual using the gun may thus easily and conveniently treat the tree from ground location.

As best illustrated in FIG. 5 sabot 14 encloses the fluid-filled envelope 17 within a cylindrical cavity defined by a plurality of semi-cylindrical side plates 18, 19, 21, rear seal plate 22, and front nose plate 23. Three side plates are preferred, although the number could be enlarged as long as the side plates together define a cylinder with an outer diameter of a caliber adapted for moving along the bore of barrel 24. Each side plate is formed with radially inwardly extending front and rear locking ridges 26, 27. The base of forward nose plate 23 is formed with a peripheral groove 28 adapted to releasably receive the three front locking ridges 26 of each side plate. Similarly, rear seal plate 22 if formed with a peripheral groove 29 adapted to releasably receive the three rear locking ridges 27 of the three plates. The abutting edges of the side plates may be formed with interlocking lips, not shown, to preclude the flexible envelope from extruding between the plates. Alternatively, this extrusion may be prevented by providing a thin paper cylinder enclosing the envelope, or by means of paper sealing strips, not shown, to seal the inner sides of the abutting edges of plates 18-21. Side plates 18-21 may be fabricated from a suitable lightweight material such as fiberglass or molded plastic so that the plates have relatively little momentum as they exit from the muzzle, and the atmosphere easily slows the velocity of the plates permitting them to fall free from the payload as it proceeds on its trajectory toward the target. The side plates thus do not impact on the target, which otherwise could result in unintended injury such as where individuals are the target.

Front nose plate 23 may be of lightweight fiberglass or molded plastic construction adapted to fall free from the payload without impacting on the target. A central aperture 31 is formed in the nose plate and functions to communicate air into the cavity of the sabot for separating the side plates. As the sabot moves from barrel 24 the build up of dynamic air pressure in front of the projectile communicates through aperture 31 into the cavity, and the differential in pressure develops an outward force acting against side plates 18-21 for separating the same from their locking relationship with the nose and seal plates. This has the effect of "exploding" the sabot elements from around the projectile to allow them to fall to the ground. Envelope 17 and the fluid payload are then free to continue on the trajectory to the target.

Rear seal plate 22 preferably is of nylon construction and is formed with an annular sealing lip 32 in tight-fitting relationship with the inner diameter of cartridge case 12. Sealing lip 32 extends rearwardly from seal plate 22 to define a pressure chamber 33 between sabot 14 and end segment 34 of cartridge base 13. Pressure within chamber 33 acts against sealing lip 32 to urge it in sliding, sealing engagement with the cartridge case and barrel as the sabot is forced from the barrel by the gas pressure acting against seal plate 22.

Cartridge 11 includes a self-contained deflagrating powder charge 36 adapted to be fired by the gun's firing mechanism to generate the desired gas pressure for moving the sabot. Powder charge 36 is of conventional composition, preferably a mixture of black gunpowder and smokeless powder, and is contained in a charge cavity defined by the rear end of seal plate 22, annular cap element 37, and disk 38, preferably of paper fabrication, mounted within the cap element. Cap element 37 includes a base segment 39 provided with a plurality of apertures or passageways 41 through which the burning gases from the powder charge expand rearwardly. A counter-sunk aperture 42 is formed in cap base segment 39 to define a seat or primer cavity receiving a conventional primer 44. This primer ignites when struck by firing pin 46 to ignite powder charge 36 through a central hole in disk 38. The powder charge burns through disk 38 and the gases explode through apertures 41 into cylindrical expansion chamber 47 mounted in gun receiver 48.

Cap element 37 threadably locks within cylindrical stub segment 49 formed in the base of rear seal plate 22 for securing the powder charge to the base of the cartridge. While a threaded connection between the cap element and stub segment is shown as preferred, it is understood that other suitable connecting means may be provided, such as high-strength cement bonding. Stub segment 49 in turn releasably fits within a large port or opening 51 formed in cartridge end segment 34. An annular groove 52 if formed at the base of port 51, and a frangible annular rim 53 is formed integral with the base of cap element 37 seats within groove 52. Rim 53 provides a break element normally locking sabot 14 to the cartridge base. Cap element 37 and its associated rim 52 are fabricated from a suitable material, such as ductile metal, nylon, or other synthetic polymer, which is effective to fracture or shear at the margin between rim 52 and cartridge base port 51 under influence of the resultant force from the predetermined gas pressure generated within chamber 47 and acting against seal plate 22 and cap element 37. A suitable selection of the cap element rim material, together with predetermined sizing of the rim dimensions, provides a degree of design selection of the pressure force which shears the rim to release the sabot from the cartridge. While an annular rim locking within a corresponding groove has been shown as the break element, it is understood that other configurations may be utilized to release the sabot at a predetermined pressure. For example, the outer periphery of the cap element could define a lip or shoulder overlapping the cartridge base with suitable scoring in the lip at which the cap would fracture under the predetermined pressure. Similarly, the cap element could be locked to the cartridge base by a tension break element or elements which fracture at the predetermined pressure.

Cartridge 11 is breech-loaded into the gun with barrel 24 "broken" to the position at 54 by forward pivoting about horizontally disposed pivot pin 56 mounted on support frame 57 extending forwardly from the lowermost portion of the receiver. Bore 58 of barrel 24 is formed at its breech end with an elongate cylindrical recess 59 adapted to receive and seat cartridge case 12. An enlarged internal recess 61 is formed in the breech to receive and seat the annulus of cartridge base 13.

Cylindrical expansion chamber 47 defines a cavity within the receiver 48 which is closed at its forward end by annular head element 62 threadably seated within the chamber. A seal ring 63 is slidably fitted within central opening 64 of head element 62, and this ring is provided with annular shoulder 66 limiting the extent of forward travel of the seal ring with respect to the head element. An annular, flat disk 67, preferably of spring-metal material, is mounted within head element 62 by means of a suitable locking device such as snap ring 68 mounted in a seating groove in the head element. Disk 67 yieldably bears against shoulder 66 of seal ring 63 urging the latter into contact with the base or rim of cap element 37. This provides a seal preventing escape of gases in the expansion chamber from between the receiver and breech. The seal ring is axially displaceable to the extent that shoulder 66 contacts head element 62 to ensure engagement of the seal ring against a cartridge as the breech is locked into place. While the sealing contact against the cap element is shown as preferred, it is understood that the seal ring could also contact cartridge base end segment 34.

Expansion chamber 47 and head element 62 are of a high strength material such as steel to contain the expanding gases. The relatively small diameter port defined by seal ring 63 results in the steel chamber and element taking the larger part of the pressure loading during firing, thereby reducing the loading on the cartridge and breech.

The firing mechanism for the gun includes firing pin 46 slidably mounted within support sleeve 69 which is centered in expansion chamber 47 and mounted within an opening 70 provided in the receiver. A compression spring 71 is provided within the support sleeve to return the firing pin to a retracted position. An enlarged head 72 formed on the firing pin projects from sleeve 69 into receiver cavity 73 which houses the trigger and hammer mechanism. The mechanism for operating the firing pin is largely conventional, and it is understood that other suitable firing devices may also be provided. A hammer 74 is pivotally mounted on pin 76 within cavity 73. A compression spring 77 mounted on spring guide 78 seated in hammer recess 79 urges the hammer toward the firing pin. A trigger 81 is pivotally mounted on pin 82 with suitable spring means 83 provided to urge the trigger clockwise as viewed in FIG. 1. A sear 84 projects from the trigger for movement into operating engagement with a notch 86 formed in the hammer. A safety device 87 is provided to prevent accidental firing of the gun. This safety device comprises a horizontally rotatable shaft having a flat 88 which turns into registry with an upwardly projecting finger 89 on the hammer. A suitable safety operating lever, not shown, may be provided for manual rotation of safety device 87.

An operating lever 91 is provided to both cock the gun and unlock the barrel for removing a spent cartridge, and to load a fresh cartridge. Lever 91 is pivotally mounted to the receiver about pin 92. A driving element 93 having a gear segment 94 is pivotally mounted on pin 92 adjacent the lever. A driving lug 96 is formed on the lever and is adapted to move into driving engagement with a shoulder 97 on the driving element. A locking pin 98 is slidably mounted within the receiver and is provided with a gear rack 99 in driving engagement with the teeth of gear segment 94. A compression spring 101 mounted within a bore in the locking pin normally urges the locking pin to the left as viewed in FIG. 1, carrying with it driving element 93 which in turn operates lever 91 to the illustrated seated position. An upwardly extending finger 103 formed integral with locking pin 98 is formed with a notch or relieved segment 104 adjacent the shoulder of firing pin head 72.

Locking pin 98 is provided with a tapered locking dog 106 for locking the barrel in firing position. This locking dog extends into engagement with a tapered detent 107 formed on fixed pin 108 mounted in the barrel frame. As lever 91 is operated for cocking the firing mechanism locking pin 98 moves rearwardly releasing locking dog 106 from detent 107. This permits the barrel to be pivoted forwardly to the position at 54 for removing the spend cartridge and inserting a fresh cartridge. With a fresh cartridge inserted in the breech, the barrel is pivoted to its seated position. At the same time, the tapered side of detent 107 engages the tapered locking dog and the resulting camming action displaces locking pin 98 rearwardly against the force of spring 101 until the elements are locked. The lost motion connection between driving element 93 and driving lug 96 permits rearward travel of locking pin 98 without moving lever 91. A suitable magnet or spring clip, not shown, may be provided on trigger guard 109 to releasably hold lever 91 in the illustrated retracted position.

In operation, gun 10 is cocked by the action of pivoting lever 91 forwardly. This drives element 93 clockwise displacing locking pin 98 to the right. Finger 103 in turn moves firing pin 46 to the right, and this action pivots hammer 74 clockwise against the compression of spring 77. Sear 84 on trigger 81 is urged by spring 83 into engagement with notch 86, and the gun is now cocked. At the same time, the rearward movement of locking pin 98 disengages detent 103 permitting the barrel to be pivoted forward.

Assume that a cartridge 11 of the type described having an envelope of water as the payload is now inserted into the breech. The barrel is returned to its seated position and locked in place as detent 107 latches against locking dog 106. With safety 87 pivoted to the illustrated position permitting free travel of hammer finger 89, the gun is ready for firing. The gun is fired by applying pressure to trigger 81 to release sear 84 from the hammer notch, permitting compression spring 77 to drive hammer 74 against the firing pin. The firing pin strikes primer 44 which ignites main powder charge 36 through the hole in the center of paper disk 38. The rapidly expanding gases of the powder charge burn through disk 38 and exhaust rearwardly through openings 41 in cap element 37. The gas fills expansion chamber 47 and builds up to a predetermined pressure, which acts against the base of the cap element and the central portion of seal plate 22. The pressure acting on these parts fractures or shears rim 53 of the cap element and sabot 14 begins initial movement from cartridge case 12. During this time seal ring 63 is urged by metal disk 67 into sealing engagement with the base of cap element 37 preventing escape of gases from between the receiver and breech. After stub segment 49 clears cartridge base 34 large area port 51 is exposed permitting a large volume of gas from the expansion chamber to enter chamber 33 and act against the full area of the seal plate. This sudden release of pressure against the sabot provides high efficiency in imparting the energy of the burning gases for moving the cartridge from the barrel. The sabot moves along the barrel as illustrated in FIG. 3 leaving the broken portion of rim 53 in the groove of cartridge base 34.

As sabot 14 exits from the muzzle the ram effect of air entering nose plate opening 31 develops dynamic pressure within the sabot forcing side plates 18-21 apart. The side plates, nose plate, and rear seal plate fall to the ground while the envelope of water continues on this trajectory to the target.

For rapid reloading, lever 91 is operated forwardly to release the barrel which is pivoted to the position at 54. The spend cartridge is then removed carrying with it the broken portion of rim 53, a fresh cartridge is inserted, and the barrel is returned to its locked, seated position. The action of unlocking the barrel simultaneously cocks the firing mechanism in the manner described for firing the next round.

While the embodiment herein is at present considered to be preferred, it is understood that numerous variations and modifications may be made therein by those skilled in the art, and it is intended to cover the appended claims all such variations and modifications as fall within the true spirit and scope of the invention.

Claims

I claim:

1. In an apparatus for propelling a fluid payload of a given weight toward a target, the combination of: a barrel having a breech for receiving a cartridge; a cartridge insertable into said breech, the cartridge including a sabot adapted to discharge from the barrel, the sabot being comprised of a plurality of segments releasably mounted together to define an internal cavity; an envelope enclosing said payload, said envelope comprising an enclosing wall of a flexible material adapted to burst under hydraulic pressure from said payload impacting with said target, the envelope being contained within said sabot cavity; expansion chamber means formed in said breech in communication with said cartridge; gas generating means to direct gas under pressure into said expansion chamber means to act against said cartridge; and means to hold the sabot against displacement with respect to the cartridge, said last mentioned means being adapted to release the sabot when the gas pressure exceeds a predetermined value for propelling the sabot from the barrel.

2. Apparatus as in claim 1 wherein said flexible material comprises a synthetic polymer formed into a film to define said enclosing wall.

3. The invention of claim 1 wherein the payload comprises a liquid, and the envelope comprises a flexible film sealingly enclosing said liquid, said envelope being adapted to burst upon impact with said target for releasing the liquid.

4. In an apparatus for propelling a fragile payload toward a target, the combination of: a barrel having a breech for receiving a cartridge; a cartridge insertable into said breech, the cartridge including a sabot adapted to discharge from the barrel, the sabot including a plurality of releasable segments normally positioned together in said cartridge to define an internal cavity, an envelope enclosing said payload, said sabot holding said envelope and payload within said cavity for movement within the barrel, and aperture means at the forward end of said sabot to communicate dynamic air pressure to within the cavity to separate said segments from the envelope and payload and allow the latter to continue on a trajectory towards said target, said plurality of segments including a rear plate, a nose plate axially spaced from the rear plate, at least three side plates each defining a segment of a cylinder, and means releasably holding said side plates with the rear and nose plates to define said cavity, said means communicating the air pressure into the cavity comprising at least one forwardly opening aperture in the nose plate; means carried by the cartridge to generate expanding gases; expansion chamber means positioned to receive the gases from the cartridge; and means to hold the sabot against displacement with respect to the cartridge, said last mentioned means being adapted to release the sabot when the gas pressure exceeds a predetermined value for propelling the sabot from the barrel.

5. In an apparatus for propelling a fragile payload toward a target, the combination of: a barrel having a breech for receiving a cartridge; a cartridge insertable into said breech and having a base adapted to seat in said breech, the cartridge including a sabot adapted to discharge from the barrel, the sabot defining an internal cavity and including rear plate means spaced from the cartridge base to define a pressure chamber; an envelope enclosing said payload, the envelope being contained within said sabot cavity; means carried by the cartridge to generate expanding gases including a deflagrating charge mounted in the cartridge, and firing means adapted to ignite said charge; expansion chamber means positioned to receive the gases from the cartridge; means to hold the sabot against displacement with respect to the cartridge, said last mentioned means being adapted to release the sabot when the gas pressure exceeds a predetermined value for propelling the sabot from the barrel; said cartridge base including port means to provide communication between the pressure chamber and expansion chamber means following initial forward displacement of the sabot.

6. The invention of claim 5 wherein the rear plate means includes centrally disposed cylindrical means releasably mounted within said port means, said cylindrical means defining a central cavity, and the deflagrating charge being positioned within the central cavity to direct said expanding gases therefrom through the port means and into the expansion chamber means.

7. In an apparatus for propelling a fragile payload toward a target, the combination of: a barrel having a breech for receiving a cartridge; a cartridge insertable into said breech, the cartridge including a sabot adapted to discharge from the barrel, the sabot defining an internal cavity, said cartridge including a cartridge base adapted to seat within said breech, said sabot including a rear plate adapted for displacement along said barrel; an envelope enclosing said payload, the envelope being contained within said sabot cavity; means carried by the cartridge to generate expanding gases; expansion chamber means positioned to receive the gases from the cartridge; and means to hold the sabot against displacement with respect to the cartridge, said last mentioned means including frangible means locking said sabot rear plate with respect to the cartridge base and adapted to break and release the sabot under influence of the resultant force against the rear plate and cartridge base developed by gas pressure within said expansion chamber means exceeding a predetermined value for propelling the sabot from the barrel.

8. The invention of claim 7 wherein the sabot rear plate includes a centrally disposed annular element, and said frangible means includes a frangible rim formed on the annular element and projecting outwardly into locking engagement with said cartridge base whereby said resultant force is effective to shear said rim from said annular element.

9. The invention of claim 8 wherein said annular element defines a charge-containing cavity, and said means to generate the gases includes a deflagrating charge positioned within said cavity, and including a plurality of apertures in said annular element providing communication between said cavity and said expansion chamber means.

10. The invention of claim 8 and further including seal ring means mounted in the apparatus for axial sliding movement, and means yieldably urging said ring means into sealing contact with the cartridge portion adjacent said breech to prevent escape of gases therebetween.

11. In an apparatus for propelling a fragile payload toward a target, the combination of: a barrel having a breech for receiving a cartridge; a cartridge insertable into said breech, the cartridge including a sabot adapted to discharge from the barrel, the sabot defining an internal cavity, the cartridge including a cartridge base being formed with a central port, said sabot including a rear seal plate adapted for movement along said barrel, said rear seal plate including a rearwardly extending cylindrical segment adapted for sliding contact with said cartridge base port, a cap element mounted within said cylindrical segment and defining a charge cavity therewith, said cap element including a base segment provided with a primer cavity; means carried by the cartridge to generate expanding gases and including a deflagrating charge contained within said charge cavity and a primer charge contained within said primer cavity, and firing means in said apparatus to ignite said primer charge; expansion chamber means positioned to receive the gases from the cartridge; said cap element base segment being formed with a plurality of passageways to provide communication between said charge cavity and said expansion chamber means; and means to hold the sabot against displacement with respect to the cartridge, said last mentioned means being adapted to release the sabot when the gas pressure exceeds a predetermined value for propelling the sabot from the barrel.

12. In a method for suppressing personnel without lethal injury thereto, the steps of propelling a projectile comprising a fluid having a weight within the range of 6 to 15 oz. contained within a flexible, burstable envelope enclosed within a protective sabot at a velocity to yield from 200 to 400 ft. lbs. of energy upon impact, releasing said sabot from said envelope, impacting only said envelope upon said personnel, and bursting said envelope against said personnel to release said fluid therefrom.

13. A method as in claim 12 wherein said sabot comprises a plurality of releasable segments, the method characterized in that the step of propelling the projectile includes directing a propelling force against the sabot and contained envelope and thereafter moving the sabot segments from the envelope whereby only the envelope and fluid traject toward said target.