US3862599A - Cased cartridge - Google Patents

Abstract

A lightweight ''''piggyback'''' propellant container is integrally formed with a warhead for travel to a target, the propellant container being imperforate and deformable upon ignition to effect substantially instantaneous exhaust of the products of combustion for launching the warhead and its propellant container from a breech of a firearm barrel.

Description

niie tet 1 Olsen States 1 Jan. 28, 1.975

1 CASED CARTRIDGE [75] Inventor: Charles R. Olsen, West Chester, Pa.

[73] Assignee: Colt Industries, Operating Corp., Hartford, Conn.

[22] Filedf Oct. 19, 1972 [21] Appl. No.: 299,003

[52] US. Cl 102/38, 102/493, 102/93 [51] Int. Cl. F42b 9/02 [58] Field of Search 102/38, 40, 43, 44, 45, 102/497, 49.3, 93

[56] References Cited UNITED STATES PATENTS 1,191,357 7/1916 Snyder 102/497 1,602,037 10/1926 Mixsell 1,812,010 6/1931 McBride 102/497 2,856,856 10/1958 Michael 102/93 2,996,012 8/1961 Butler 102/93 3,687,079 8/1972 Scollins.. 102/93 X 3,724,377 3/1973 Birkigt [OZ/49.7

Primary Examiner-Benjamin A. Borchelt Assistant Examiner-H. J. Tudor Attorney, Agent, or FirmPrutzman, Hayes, Kalb & Chilton I [57] ABSTRACT A lightweight piggyback" propellant container is integrally formed with a warhead for travel to a target, the propellant container being imperforate and deformable upon ignition to effect substantially instantaneous exhaust of the products of combustion for launching the warhead and its propellant container from a breech of a firearm barrel.

7 Claims, 5 Drawing Figures PAINTED- 3,862,599

sum 20F 2 FIG. 5 17/ f CASED CARTRIDGE This invention generally relates to projectiles and particularly to a cased cartridge of a so-called monopressure type which is propelled from a firearm barrel as an integral mass.

A primary object of this invention is to provide a new and improved cased cartridge having a warhead and integral lightweight propellant container at its breech end forming a sealed propellant compartment particularly suited to be. launched from a firearm barrel such as a launch tube and carried to a target with the warhead.

A further object of this invention is to provide such a cartridge which eliminates any need for extraction of empty cartridge cases. i

A still further object is to provide such a cartridge which virtually precludes pre-ignition from radiant energy and effectively prevents such spontaneous preignition of a cartridge upon its being advanced by a feed mechanism to battery position.

Another object of this invention is to provide such a cartridge wherein its propellant container is formsustaining but deformable upon firing to expand in a controlled manner to effect substantially instantaneous exhaust of the products of propellant combustion for launching the warhead together with its propellant container from a fire-arm barrel.

A still further object of this invention is to provide such a cased cartridge exhibiting the additional advantageous characteristic of effective obturation.

A still further object of this invention is to provide a cased cartridge of the type described having additional advantages of minimizing the weight and cost of conventional metallic cases, simplifying the associated weapon system by eliminating any requirement for manual or automatic extraction or ejection after firing while obtaining the benefits of conventional cased cartridges in preserving the mechanical integrity of the round to readily permit conventional storage and handling and at the same time being highly resistant to adverse effects of moisture, mold, etc. under widely varying and sometimes demanding environmental conditions.

Still another object of this invention is to provide such a cased cartridge which is quickly and easily manufactured and assembled.

Other objects will be in part obvious and in part pointed out in more detail hereinafter.

A better understanding of the objects, advantages, features, properties and relationships of the invention will be obtained from the following detailed description and accompanying drawings which set forth certain illustrative embodiments and are indicative of the ways in which the principle of the invention is employed.

In the drawings:

FIG. 1 is a sideview of a cartridge, partly broken away and partly in section, incorporating this inventron;

FIG. 2 is a partial side view of an end portion of a cartridge, partly broken away and partly in section, incorporating another embodiment of this invention and showing a portion of a firearm barrel from which the cartridge is launched;

FIG. 3 is an end view of the projectile of FIG. 2 shown prior to its being fired;

FIG. 4 is a longitudinal section view of a cartridge incorporating still another embodiment of this invention; and

FIG. 5 is a partial side view, partly broken away and partly in section, showing an end portion of a cartridge incorporating another embodiment of this invention.

Referring to the drawings in detail, a cased cartridge 10 having a generally cylindrical warhead or projectile is illustrated in FIG. 1 having a nose portion 14 which would be directed toward a target and a breech portion 16 carrying a propellant container 18. Encased within the container 18 is a combustible propellant 20 of conventional type which upon ignition serves to launch the cartridge 10 toward a target. The propellant container 18 is preferably formed from a cup-shaped lightweight form-sustaining but deformable material such as aluminum, e.g., and includes a generally annular side wall 22 which in FIG. 1 is integral with an end wall 24 and a forward wall 26 fixed to a rear of the projectile 12 by any suitable means such as an igniter 28 secured to a threaded projection 30 extending coaxially from the rear of projectile 12.

The igniter 28 is a hollow cylindrical component having radial passages 32 communicating a central opening 34 of the igniter 28 with an internal propellant compartment 36 defined within propellant container 18. While a suitable electric primer of conventional type may be provided, the preferred embodiment is shown having a typical percussion primer 38 mounted in an extreme rear portion of the central opening 34 in the igniter 28 whereby the rear end of the primer 38 is exposed for impact ignition by a conventional percussion element of a firearm such as a launch tube, not shown, from which the cartridge 10 is to be launched. The radial passages 32 in the igniter 28 are preferably closed off by combustible tape such as at 40 and a cardboard wad 42, e.g., may be mounted in a forward portion of the central opening 34 whereby a suitable ignition mix 44 is effectively sealed within the igniter 28.

By virtue of the above described construction, the

end wall 24 of the propellant container 18 may be suitably crimped in position as at 46 wherein a deformable elastomeric tube 47 is fitted around a crimped annular central portion of end wall 24 and releasably retained in position about the adjacent outer periphery of igniter 28. Such construction ensures that the internal propellant compartment 36 is sealed off against entry of moisture, dirt and other undesirable contaminants and thereby prevents deterioration which effects burning not only of the ignition mix 44 within the igniter 28 but also the propellant 20 within the compartment 36 upon firing of primer 38.

To effect a controlled rupture of the enclosed sealed propellant compartment 36 in accordance with this invention, the side and end walls 22 and 24 of the propellant container 18 are suitably dimensioned and configured such that pressure build-up to a predetermined optimum level within compartment 36 upon ignition of the propellant 20 causes the normally sealed and crimped annular central portion of end wall 24 at 46 to be blown open as indicated by broken lines at 48 to substantially instantaneously exhaust the products of propelant combustion for launching projectile 12 and its propellant container 18 in its entirety from the barrel or launch tube.

To effectively obturate a closed breech end of a firearm barrel, an obturator band 50 is shown secured to the breech end of the cartridge 10 such that upon being driven up the taper of the projectile boat-tail by gas pressure during propellant combustion, the obturator band 50 will be forced into sealing engagement with the internal wall of the firearm barrel. If desired, the obturator band 50 may be formed of a tough impactresistant form-sustaining plastic such as nylon and may be mechanically snap-fit over adjacent knurled portions such as at 52 at the rear of the projectile l2 and the container side wall 22 to provide a rough surface for the obturator band 50 to grasp and to provide a driving torque to rotate the projectile with a spin velocity. The firearm barrel may be provided with conventional lands 54 and grooves 56, such as in barrel 58 illustrated in FIG. 2, thereby ensuring that a high spin velocity is imparted to the cartridge about its major longitudinal axis upon launch. To minimize turbulent drag during flight, controlled fracture of the band 50 may be intentionally effected to provide band discard shortly beyond the firearm muzzle under centrifugal force while the cartridge 10 is spinning at high velocity. In this regard, the obturator band 50 if desired may be scored by premolding such as at 60 to fracture and effect discard of the obturator band 50 after'launch for improved aerodynamic characteristics, e.g., whereby the rearwardly tapered configuration of the propellant container 18 provides a boat-tail effect.

It should be also noted that the igniter 28 is formed with an extractor groove 62 which facilitates removal of the cartridge 10 from the barrel for any reason before firing or in the event of misfire, etc. Moreover, for improved sealing within the propellant compartment 36 and the igniter 28 to preserve the integrity of the propellant charge and ignition mix 44 during storage, e.g., theigniter is preferably formed of a suitable metal to further preclude the entrance of any unwanted moisture, etc., into the igniter passages and the propellant compartment.

In FIG. 2 there is illustrated a modified cased cartridge 110 having a projectile 112 and attached propellant container 118 defining a compartment 136 for receiving a combustible propellant 120 all of which are substantially identical in construction and characteristics as that described in connection with the embodiment of FIG. 1. The igniter 128 has a generally tubular body with communicating passageways 132, 132 extending generally radially from a central opening 134 which may contain a suitable ignition mix 144 and which is closed at its extreme rear end portion by a primer 138. The forward end of the central opening 134 15 closed and, if desired, may be provided with a suitable tracer mix, not shown, since the igniter 128 is shown affixed to a rear of the projectile 112 and it carried with it during launch from barrel 58. The leading end of obturator band 150 is snap-fitted over side wall 122 of propellant container 118 which in turn is crimped into position as at 170 about groove 171 in a breech end of projectile 112. The end wall 124 at the breech end of projectile 112 is releasably crimped between tube 147 and igniter 128 as described in FIG. 1 to provide a desired seal against foreign matter while at the same time subject to rupture to substantially instantaneously vent the gaseous byproducts of propellant combustion at the juncture of container 118 and igniter 128. As best seen in FIG. 3, the propellant compartment end wall 124 is formed in a rose-crimp arrangement radiating outwardly from the coaxially disposed ingiter 128. As a further illustration of the type of modification permitted with this cased cartridge 110, the obturator band 150 is formed with a suitable extractor cannelure 172. In addition, the entire container side wall 122 and end wall assembly together with the obturator band 150 may be fractured off, if desired, for improved aerodynamic characteristics in flight after the projectile 112 has been launched from the firearm barrel 58.

If desired, cased cartridge of this invention may be provided with a maximum outer diameter less than the minimum internal diameter'of firearm barrel 58 such that the cartridge 110 may be utilized as a mortar, for example, to be dropped into a mortar tube such as that of barrel 58 to detonate the primer 138 causing heat and shock ignition of the projectile propellant to drive projectile 112 with its propellant container 110 out of the mortar tube upon ignition of the base charge 120 and rupture of the propellant container 118 to exert thrust to the cartridge 110 from the breech end of the mortar tube. Localized expansion of the obturator band effects positive physical engagement with the lands 54' and grooves 56 of barrel 58 to not only seal off the breech end of the barrel 58 but to also ensure that a spin velocity will be imparted to the projectile 112 for maximizing accuracy of the projectile trajectory.

Still another embodiment of this invention is shown in FIG. 4 wherein side wall 222 of propellant container 218 is integrally formed by a rearwardly extending portion of projectile 212 surrounding a cavity in the breech end portion 216 of the cartridge 210 for receiving a base charge 220. A closure disc 224 serves as an end wall for sealing propellant compartment 236 and, in the illustrated embodiment, is shown secured in position by an igniter 228 threadably secured within an axial opening 280 of reduced size formed in the rear of projectile 212 in communication with its propellant compartment 236. Internal axial opening 234 within igniter 128 and its communicating radial passages 232, 232 are substantially the same as previously described, as is primer 238 located at the rear of the igniter 228. Ignition of mix 244 within the igniter opening 234 causes the burning of tape 240, which normally closes off communicating passages 232, 232 and the subsequent combustion of propellant 220 within main propellant compartment 236. Combustion of propellant 220 will build up gas pressure, distort and fracture the end wall seal at the outer periphery of disc 224 where it engages the projectile side wall 222 to substantially instantaneously release combustion gases into a breech of a firearm barrel to launch cased cartridge210. For completeness, it is also noted that cartridge 210 of FIG. 4 is shown with an obturator band 250 integrally formed on the projectile body. Also, as previously described, breech portion 216 of the cartridge 210 is preferably tapered for improved aerodynamic characteristics.

FIG. 5 shows another embodiment of this invention wherein combustible propellant 320 is encased in a short tubular propellant container 318, formed, e.g., of aluminum, and comprising the rear of projectile 312.

If desired, a tracer assembly 390 may be mounted within main propellant compartment 336 upon fitting the tracer assembly 390 onto an inner end portion of igniter 328. A suitable tracer mix 391 is disposed within tracer assembly sleeves 392 having open ends positioned adjacent an annular end portion of container 318. A closure disc 324 is placed over igniter 328 and expanded into a groove 394 in the propellant container 318. Thereafter, the terminal end of igniter 328 is rolled over to form a retaining lip 395 for the closure disc 324 and to seal the propellant compartment 336. Upon firing, the closure disc 324 partially opens about its outer periphery at its juncture with the propellant container 318, allowing the propellant gas to escape substantially instantaneously into the chamber of the launch tube or firearm barrel, not shown, to launch the cased cartridge 310. The burning of the propellant 320 causes ignition of the tracer mix 391 which escapes past the outer periphery of the distorted disc 324. While the tracer assembly 390 is shown in the embodiment of FIG. 5, obviously such an assembly may be optional depending on the requirements to which the cartridge 310 is to be applied.

From the foregoing description, it will be appreciated that a cased cartridge of the type described incorporates a construction particularly suited to provide a water'proof, weather-proof round which preserves the mechanical integrity of the ammunition during storage, handling, ramming, etc. while also providing for convenient extraction for unloading chambered cartridges should such extraction be desired. Normally, no ejection and no extraction is encountered upon firing of a round thereby significantly simplifying the operating components of the associated weapon. Moreover, such advantages have been achieved in the design of this invention while providing the additional advantages of elimination of weight and cost of a conventional metallic case in addition to eliminating any undesired residue in a breech end of the weapon for launching the cartridge of this invention, since the entire cartridge including its lightweight piggyback propellant compartment is carried with the projectile upon launch. The aluminum case additionally serves to reflect radiant heat and accordingly minimizes any chance of premature ignition of the cartridges being advanced into battery position.

As will be apparent to persons skilled in the art, various modifications, adaptations and variations of the foregoing specific disclosure can be made without departing from the teachings of the present invention.

I claim:

l. A cased cartridge for firing as an integral unit from a breech of a firearm barrel comprising a projectile, a propellant container carried on a rear portion of said projectile, said propellant container having an annular side wall and an end wall on a breech end of said projectile, said side and end walls being formed of imperforate form sustaining noncombustible material jointly defining and normally sealing an enclosed propellant containing compartment, said projectile having a ta pered rear side wall configuration providing a tapered boat-tail on the rear of said projectile, an obturator band mounted in surrounding relation to said tapered boat-tail of said projectile to effect obturation of propellant gases upon being driven up the projectile boattail by'the gaseous products of combustion, and a combustilble propellant received within said compartment, said propellant container being deformable such that pressure buildup to a predetermined level within said compartment upon ignition of said propellant causes controlled rupture of the enclosed sealed compartment and effects substantially instantaneous exhaust of products of combustion for launching said cartridge in its entirety from the firearm barrel.

2. The cartridge of claim 1 in combination with the firearm barrel having rifling lands and grooves, and wherein expansion of the gaseous products of combustion effects driving movement of said obturator band along said tapered boat-tail of said projectile into positive physical engagement with the rifling lands and grooves ofthe firearm barrel to form a seal and provide a driving torque to impart a spin velocity to said cartridge upon its being launched from the firearm barrel in a direction along the cartridge spin axis.

3. The combination of claim 2 wherein said obturator band is formed of a frangible material and is detachable after launch during flight.

4. The cartridge of claim 2 wherein said obturator band is formed of a tough impact resistant, formsustaining plastic.

5. The cartridge of claim 4 wherein said obturator band and said projectile are mutually dimensioned and configured to permit snap-on connection of said obturator band in an assembled unit providing positive mechanical engagement between said obturator band and said projectile.

6. The cartridge of claim 2 wherein the projectile includes a knurled portion in contact engagement with the obturator band about the projectile to impart said driving torque.

7. The cartridge of claim 1 wherein said propellant container side wall is detachably mounted on said tapered boat-tail on the rear of said projectile to be launched with said projectile as an integral unit while permitting discard of at least a portion of said propellant container after launch during flight.

Claims (7)

1. A cased cartridge for firing as an integral unit from a breech of a firearm barrel comprising a projectile, a propellant container carried on a rear portion of said projectile, said propellant container having an annular side wall and an end wall on a breech end of said projectile, said side and end walls being formed of imperforate form sustaining noncombustible material jointly defining and normally sealing an enclosed propellant containing compartment, said projectile having a tapered rear side wall configuration providing a tapered boat-tail on the rear of said projectile, an obturator band mounted in surrounding relation to said tapered boat-tail of said projectile to effect obturation of propellant gases upon being driven up the projectile boat-tail by the gaseous products of combustion, and a combustilble propellant received within said compartment, said propellant container being deformable such that pressure build-up to a predetermined level within said compartment upon ignition of said propellant causes controlled rupture of the enclosed sealed compartment and effects substantially instantaneous exhaust of products of combustion for launching said cartridge in its entirety from the firearm barrel.

2. The cartridge of claim 1 in combination with the firearm barrel having rifling lands and grooves, and wherein expansion of the gaseous products of combustion effects driving movement of said obturator band along said tapered boat-tail of said projectile into positive physical engagement with the rifling lands and grooves of the firearm barrel to form a seal and provide a driving torque to impart a spin velocity to said cartridge upon its being launched from the firearm barrel in a direction along the cartridge spin axis.

3. The combination of claim 2 wherein said obturator band is formed of a frangible material and is detachable after launch during flight.

4. The cartridge of claim 2 wherein said obturator band is formed of a tough impact resistant, form-sustaining plastic.

5. The cartridge of claim 4 wherein said obturator band and said projectile are mutually dimensioned and configured to permit snap-on connection of said obturator band in an assembled unit providing positive mechanical engagement between said obturator band and said projectile.

6. The cartridge of claim 2 wherein the projectile includes a knurled portion in contact engagement with the obturator band about the projectile to impart said driving torque.

7. The cartridge of claim 1 wherein said propellant container side wall is detachably mounted on said tapered boat-tail on the rear of said projectile to be launched with said projectile as an integral unit while permitting discard of at least a portion of said propellant container after launch during flight.

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