Cartridged Ammunition

The invention relates to cartridged ammunition for a grenade pistol, the ammunition being of the type that includes a casing having an opening, a projectile which is disposed in the opening and which includes a payload and a transfer charge (such as a tracer charge and/or a delayed-action charge) for the payload, and primer and propelling charges disposed in a cup at the base of the casing.

Cartridge ammunition for a grenade pistol is disclosed in German Offenlegungsschrift (unexamined laid-open application) No. 3,149,430. The prior art ammunition includes a metal propelling charge container or casing (made, for example, of aluminum) with which the grenade body of the projectile is crimped together. Primer and propelling charges are disposed in a cup-shaped propelling charge cartridge which is screwed into the base of the casing. Radially extending discharge openings permit, after firing of the propelling charge, propagation of the propellant gases into the interior of the casing and charge the tail of the projectile with propellant gas pressure.

To save costs, the casing of cartridged practice ammunition is preferably made of plastic and, since crimping is then not possible, the casing must be connected with the generally metal projectile body by glue.

However, glue connections have the drawback that, in spite of carfeul matching and monitoring of all manufacturing parameters, even within one and the same lot, different degrees of extraction forces are observed. Additionally the extraction forces is a function of temperature and aging. Since, moreover, a considerably smaller propelling charge is employed for practice ammunition compared to combat ammunition, a particularly disadvantageous temperature dependency of the propellant gas pressure results when the propellant gases exit from the propelling charge cartridge or the propelling charge cup into the large-volume interior of the propelling charge casing. Both effects have the drawback of producing greatly deviating values for the initial velocity (V.sub.0) of the projectile, and reproducible firing results are almost impossible to attain. In connection with prior art projectiles it was additionally noted that, due to the escape of propellant gases into the interior of the casing, the tracer or delayed-action charge disposed in the tail section of the projectile is not fired with sufficient reliability.

It is an object of the invention to improve cartridged ammunition for a grenade pistol to the extent that the above-described drawbacks are avoided and, primarily because of a constant, almost temperature independent initial velocity, firing results are realized which are reproducible over a broad temperature range as well as reliable ignition of the tracer and/or delayed-action charge.

Based on cartridged ammunition of the above defined type, this is accomplished by providing the cup which accommodates the priming and propelling charges in the form of two mutually concentric sleeves, with the inner sleeve being mounted in the outer sleeve so as to be slidable and extendable in the manner of a telescope. The inner sleeve is cup-shaped and is provided, in its bottom, with a firing channel oriented toward the tracer charge and the delayed-action charge. The outer sleeve has a free end section which is provided with an external thread followed by an annular, circumferential predetermined break location. The base of the projectile includes a sleeve having an internal thread which is screwed onto the outer sleeve of the cup.

FIG. 1 is a view in longitudinal section illustrating the ammunition in its rest or un-fired state;

FIG. 2 is a view in longitudinal section illustrating the ammunition a short time after firing of the propelling charge;

FIG. 3 is a view in longitudinal section illustrating the ammunition after separation of the projectile from the casing;

FIG. 4 is a view in longitudinal section illustrating a modified embodiment of the ammunition, with recesses provided in the sleeve of the cup;

FIG. 5 is a side view of a portion of a sleeve illustrated in FIG. 4;

FIG. 6 is a sectional view through a portion of the sleeve of FIG. 5; and

FIG. 7 is a side view of a portion of a sleeve in a further modified embodiment.

FIG. 1 is a longitudinal sectional view of a cartridged ammunition for a grenade pistol, for example having a caliber of 40 mm. Ammunition 1 includes a casing 10 made, for example, of plastic, with a projectile 11 being disposed in its opening. The projectile is equipped, for example, with a smoke chrge 11a and a tracer charge and/or delayed-action charge 11b disposed in the tail section of projectile 11. A primer 13 and a propelling charge 14 are accommodated in a cup 12 disposed at the base of casing 10. Cup 12 is composed of two mutually concentrically arranged sleeves 12a and 12b. Inner sleeve 12b is cup-shaped and is mounted so as to slide in outer sleeve 12a and to be extended in a telescoping manner. The inner sleeve 12b is provided in its bottom or end wall 12e with a firing channel 12c oriented toward the tracer and/or delayed-action charge 11b in the tail section of projectile 11.

The free end sectionof outer sleeve 12a extends into the interior 10a of casing 10 and is provided with an external thread 100 followed by an annular, circumferential predetermined break location 12d. The base of projectile 11 is provided with a sleeve 17 provided with an internal thread so that it can be screwed onto outer sleeve 12a of cup 12.

Due to the above-described structure, the ammunition can be assembled in a particularly easy and economical manner. After inserting cup 12 containing primer 13 and propelling charge 14 into the base of casing 10, an O-ring 15 is initially placed into the annular, circumferential, predetermined break location 12d in the outer jacket of outer sleeve 12a of cup 12. Then, projectile 11 is screwed by means of sleeve 17 onto external thread 100 of cup 12 until casing 10 and projectile 11 are seated flush on top of one another. Thus there is no gluing of the plastic casing 10 to projectile 11, so that all the above-described drawbacks connected with glue connections are avoided. If a metal casing is employed, crimping is no longer necessary. The O-ring 15 placed into predetermined break location 12d reliably seals the screw connection against any moisture that might still reach the interior 10a of casing 10, so that the cartridged ammunition remains reliably operational even after very long periods of storage.

The functioning of the ammunition will be described with reference to FIGS. 2 and 3. After the firing of propelling charge 14 by way of primer 13, a gas pressure develops in the propelling charge chamber in cup 12, which causes the annular predetermined, break location 12d thus stressed with tension to yield only after a predetermined and easily reproduced pressure level is reached.

After predetermined break location 12d has been torn apart, the propelling charge pressure causes projectile 11 to be accelerated and begins to push it out of propelling charge casing 10. However, the volume available for the propellant gases is enlarged only comparatively slightly since the cup-shaped inner sleeve 12b (which, as previously noted, is slidably mounted so as to be extended in a telescope-like manner in outer sleeve 12a of cup 12) is pressed out of outer sleeve 12a in a telescope-like manner when it participates in the movement of the projectile. This limits the volume of the propellant gas and prevents escape of propellant gases into the interior 10a of casing 10. Only after projectile 11 leaves the cartridge base--as shown in FIG. 3--and enters the rifling of the gun barrel (not shown), practically at its final velocity, will inner sleeve 12b, which is now completely separated from outer sleeve 12a, open a path for the propellant gases to enter into the interior 10a of casing 10. Due to the very tightly limited small volume in which the propellant gases are initially able to propagate, there results, in an advantageous manner, a greatly reduced temperature dependence of the propellant gas pressure which again, in spite of greatly differing ambient temperatures, leads to a constant initial velocity for projectile 11 and thus to reproducible firing results.

Limiting of the propellant gas volume to a volume that is small initially is known per se from German Auslegeschrift (examined laid-open application) No. 2,262,981. However, in that publication, a ductile cup is provided in a disadvantageous manner to delimit the propelling charge chamber which, under the influence of the propellant gases, must be bulged out by deformation forces.

The firing channel 12c in the end wall 12e of cup-shaped inner sleeve 12b is oriented toward the tracer and/or delayed-action charge 11b disposed in the tail section of projectile 11. Immediately after firing of propelling charge 14, hot propellant gases are thus able to pass through this firing channel 12c. This permits--in contrast to conventional ammunition--a completely reliable firing of the tracer and/or delayed-action charge 11b.

Tracer and/or delayed-action charge 11b simultaneously serves to provide for firing, possibly with a time delay, of a payload transported in projectile 11, here, for example, a smoke charge 11a. For this purpose, casing 110 which accommodates the tracer and/or delayed-action charge 11b is pyrotechnically coupled with the smoke charge 11a in such a manner that toward the end of the burning period of tracer and/or delayed-action charge 11b, smoke charge 11a is also fired. Thus pressure builds up in projectile 11 which, after causing an O-ring 16 to be blown off, permits clouds of smoke 19 to escape, as shown in FIG. 3, preferably through bores 18 uniformly distributed in a annular pattern. In this way, an effective smoke effect is produced even while the projectile 11 is in its last phase of flight, before it hits the ground. Instead of the smoke charge 11a, another payload, such as, for example, a flash, muzzle report, dye and/or fogging charge, may of course also be disposed in projectile 11.

Advantageous modifications of the invention will be described with reference to FIGS. 4 to 7. FIG. 4 is a longitudinal sectional view of a practice cartridge, FIG. 5 is a side view of the cup 12' which is shown to a larger scale; FIG. 6 is a sectional view--again enlarged--through the wall of cup 12' in the region of recesses 50; and FIG. 7 is a side view of a cup 12" in another embodiment.

The advantageous modifications of the ammunition 1' differ from the embodiment according to FIGS. 1 to 3 primarily in that recess 50 are provided in the wall of cup 12' so as to connect the chamber of propelling charge 14 with the interior 10a of casing 10. Each recess 50 may have a diameter between 0.5 mm and 2.5 mm, and preferably about 2 mm. These recesses 50 are preferably uniformly distributed in an annular pattern, in the embodiment according to FIGS. 5 to 6, below predetermined break location 12d.

In one embodiment of the invention, four recesses 50 are provided at a mutual spacing of 90.degree.. Due to the provision of recesses 50, after propelling charge 14 is fired the interior 10a of casing 10 is also charged with a gas pressure right from the beginning, albeit a lower gas pressure. In view of the large difference in volume between the propelling charge chamber within cup 12' and the interior 10a of casing 10, the pressure value encountered in interior 10a is lower, for example only 1/10 of the pressure in the interior of cup 12'. Since, however, projectile 11 delimits interior 10a of casing 10 with a relatively large surface area, a great force is exerted projectile 11 in spite of the relatively low gas pressure in interior 10a, which force contributes to the separation between projectile 11 and casing 10.

In this modification of the invention, the predetermined break location 12d has such dimensions that it could not be destroyed merely on the basis of the propelling charge pressure developed in the interior of cup 12'. For example, predetermined break location 12d could be designed so that it would be destroyed only under a load of 750 kp. However, an internal pressure of about 400 bar in the interior of cup 12a and a surface area of about 1.25 cm.sup.2 would develop only a force of about 500 kg. Only a combination of the forces acting on the projectile, due to the pressure in the interior of cup 12a and in the interior 10a of casing 10, makes it possible to destroy predetermined break location 12d and accelerate projectile 11. The contributing pressure in interior 10a of casing 10 is here about 50 bar, which exerts an additional force of 500 kp on the base surface of the projectile of about 10 cm.sup.2. Thus, only the sum of the above mentioned force components exceeds the break resistance of predetermined break location 12d.

Due to the fact that interior 10a is already preheated by the penetrated propellant gases and is charged with a certain pressure level, a significantly greater precision with respect to reproducibility of the initial velocity are range of projectile 11 can be realized.

In one embodiment of the invention, the outer diameter of casing 10 was about 38 mm, the inner diameter of cup 12' about 12 to 13 mm. Four recesses 50, each having a maximum diameter of about 2 mm, were disposed in cup12' at mutual spacings of 90.degree.. The weight of the projectile was about 180 g. With propellant charge 14 having a weight of about 0.35 g, a pressure of about 500 bar developed in the interior of cup 12', while about 1/10 of this pressure value, i.e. 50 bar, was noted in interior 10a of casing 10. After numerous test firings, a very uniform initial velocity was noted for projectile 11 and the range remained constant with a very low standard deviation, so that all requirements of the customer should be met. The spread in range was always below about 25 cm per 100 m, compared to about 45 cm per 100 m for conventional ammunition. The standard deviation of the initial velocity V.sub.o was always less than 1 m sec.sup.-1. Thus the values required by the customer could be maintained without difficulty.

To improve the storage life of the cartridged ammunition and to make it less susceptible to moisture, it is advisable to cover recesses 50 with a membrane 50a--as shown in FIG. 6--which is not pressure resistant but is destroyed immediately after firing of propelling charge 14. This membrane 50a may be produced, for example, of a thin plastic or metal foil.

In a further embodiment of the invention, recesses 50 in cup 12" are advisably disposed so as to lie within annular, predetermined break location 12d (FIG. 7). This embodiment has the advantage that no separate cover is required for recesses 50, for example as shown in FIG. 6 reliable sealing of recesses 50 is simultaneously effected by O-ring 15, which is inserted into the predetermined break location 12d so as to seal the screw connection between sleeve 17 and cup 12".