WO2001098727A1

WO2001098727A1 - Shot cartridge

Info

Publication number: WO2001098727A1
Application number: PCT/SE2001/000995
Authority: WO
Inventors: Margaretha Andersson
Original assignee: Margaretha Andersson
Priority date: 2000-05-09
Filing date: 2001-05-08
Publication date: 2001-12-27
Also published as: SE0001709D0; AU9610601A; SE0001709L

Abstract

A shot cartridge (7) comprises a shell (2) with an outlet end (4), and a multiplicity of elongate projectiles (8) provided in the shell. Each projectile (8) has an impact end (9) and a rearward end (10) and is asymmetrically shaped so that its centre of gravity is situated closer to the impact end (9) than the rearward end (10). The projectiles behave as arrows when the shot cartridge is fired by a shot gun, which makes it possible to make the projectiles from an environmentally friendly material lighter than lead without reducing the striking energy of the projectiles as compared to traditional spherical lead small shots.

Description

SHOT CARTRIDGE

The present invention relates to a shot cartridge, comprising a shell with a bottom and an outlet end, a powder charge provided in the shell at the bottom thereof, and a plurality of elongate projectiles consisting of a material lighter than lead and provided in the shell above the powder charge. Each projectile has an impact end and a rearward end and is asymmetrically shaped so that its centre of gravity is situated closer to the impact end than the rearward end.

The traditional shot cartridge contains projectiles in the form of small shots of relatively small spherical lead bullets, as for example disclosed in the Swedish patent specification SE 508 600 C2. When shooting with a shot cartridge the small shots leave the shot gun in the form of a cluster of small shots, which achieves sufficient striking energy thanks to the fact that the small shots thus are made of lead having a high density.

However, lead is an ecologically harmful heavy metal, which means that for ecological reasons it is objectionable to use lead small shots. In consequence, the authorities in many countries have initiated restrictions with respect to the use of lead small shots and probably will initiate total prohibition as soon as satisfactory replacements are offered.

One has tried to fabricate small shots from other materials of relatively high density, such as wolfram, bismuth and molybdenum. However, shot cartridges with such alternative small shots will be about twice as^' expensive as traditional lead shot cartridges. Besides, it has been proved that these alternative small shots easily crack and give poorer hit results.

One has also proposed to use a stronger powder charge in shot cartridges with small shots of a material lighter than lead, such as steel. Such shot cartridges costs about as much as traditional shot cartridges but can usually not be used for older shot guns . A drawback to steel small shots is that they have a poorer force of impact than lead small shots and therefore often give rise to crippled animals that have to be traced to be finally put away. Another draw back to steel small shots is that they may give dangerous ricochets, and in consequence the shot has to wear protective goggles . Besides, steel small shots that have fastened in trees are hard enough to damage the saw-blades of the sawmills .

WO 95/10753 discloses a shot cartridge containing non- spherical elongate small shots of a lead-free material. The small shots have a symmetrical shape and are stacked, short end to short end, in the shell of the shot cartridge .

The object of the present invention is to provide a new shot cartridge, which is more environmentally friendly than the traditional shot cartridge without being less efficient for this sake.

This object is obtained by a shot cartridge of the kind stated initially characterised in that each projectile is designed with such a length that the relation between the weight and target surface of the projectile at least substantially corresponds to the corresponding relation of a spherical lead bullet, whereby the striking energy of the projectile will be substantially the same as that of said lead bullet. The expression ⁿat least substantially corresponding"is intended to mean that minor divergences between said relations may be allowed as long as the striking energy of the projectile according to the invention will be substantially the same as that of the traditional lead bullet. The present invention is based on the fact that when a shot cartridge according to the invention is fired the projectiles will orient in the air and behave as arrows and hit the target with their impact ends leading. Thus, the projectiles can be fabricated from an environmentally more friendly material than lead, even if the material has a substantially lower density than lead, since the lower density simply is compensated by making the projectiles longer so that the striking energy will be substantially the same as for lead bullets having the same target area as the elongated projectiles.

Alternatively, the projectiles may be designed slimmer than traditional lead bullets, which is compensated by prolonging the projectiles even more.

The projectiles may be freely packed in the shot cartridge without being oriented in any particular manner. However, with advantage the projectiles may be oriented in the shot cartridge with there impact ends directed towards the outlet end of the shot cartridge . As a result the impact force of the projectiles is increased, since the projectiles already when they leave the shot cartridge after firing have the correct "arrow orientation" and do not need to turn during the flight to assume the correct arrow orientation.

Preferably, the projectiles are nested in the shot cartridge, so that the upper projectiles of two nested projectiles rests with its rearward end on the impact end of the lower projectile. The projectiles suitably form a plurality of stacks of nested projectiles filling the shot cartridge. As a result, a maximum number of projectiles can be filled in the shot cartridge.

According to a preferred embodiment of the shot cartridge according to the invention, each projectile comprises a tapering impact head at its impact end and a recess at its rearward end at least substantially complementary shaped to the impact head, so that the impact head of a projectile is insertable into the recess of another projectile. As a result, the projectiles in each stack are fixed to one another.

The impact head and recess, respectively, of each projectile may take the shape of for example a cone, a segment of a sphere, a pyramid or the like.

The present invention also relates to a new projectile for use in a shot cartridge of the kind containing a multiplicity of projectiles. The new projectile is elongated and comprises an impact end and a rearward end, wherein the projectile is asymmetrically shaped so that its centre of gravity is situated closer to the impact end then the rearward end. The projectile is designed with such a length that its relation between the weight and target surface and, consequently, its striking energy at least substantially corresponds to the corresponding relation of a spherical lead bullet . Preferably, the projectile comprises a tapering impact head at its impact end and a recess at its rearward end shaped at least substantially complementary to the impact head, so that the impact head of the projectile can be inserted into the recess of another similar projectile.

In case the projectile is designed as an elongate cylindrical stick its length can be calculated from the following formulae :

a) m^ = 4πr³ /p_pb

b) m,. = πr²lp_x

where rti_pj_o is the weight of a spherical lead bullet p_pb is the density of lead r is the radius of the cylindrical projectile m^ is the wheight of the projectile

1 is the length of the projectile p_x is the density of the projectile

The combination of a) and b) gives:

1/r = 4p_x/3p_pb If the shape of the projectile differs from a cylindrical stick the above formulae have to be modified in response to the differing shape. For example, the target surface A

= πr²

The invention is described in more detail in the following with reference to the accompanying drawing, in which:

Figure 1 shows a traditional shot cartridge with spherical lead small shots,

Figure 2 shows an example of a shot cartridge according to the invention, and

Figures 3A-3E show five embodiments, respectively, of a projectile according to the invention for use in the shot cartridge according to figure 2.

In the figures similar details have been provided with the same reference numerals .

In figure 1 there is shown a traditional shot cartridge 1 comprising a shell 2 with a bottom wall 3 and an outlet end 4. The shell 2 contains a powder charge 5 closest to the bottom wall 3 and a number of spherical lead small shots 6 on top of the powder charge 5.

In figure 2 there is shown an example of a new shot cartridge 7 according to the invention of the same kind as the traditional shot cartridge 1, except that the new shot cartridge 7 is provided with elongate projectiles 8 of a material more environmentally friendly then lead. Each projectile 8 has an impact end 9 and a rearward end

10, wherein the projectile 8 is oriented longitudinally in the shell 2 with its impact end 9 directed toward the outlet end 4. (Alternatively, the projectiles 8 may be oriented in random in the shell 2) . Each projectile 8 is designed with such a length that its relation between the weight and target surface and, consequently, its striking energy at least substantially corresponds to the corresponding relation of a traditional spherical lead bullet.

Furthermore, the projectile 8 comprises a tapering impact head 11 at its impact end 9 and a recess 12 at its rearward end 10 shaped complementary to the impact head

11. As a result, the projectile 8 assumes an asymmetrical shape, which means that the centre of gravity of the projectile 8 will be situated closer to the impact end 9 than the rearward end 10. The projectiles 8 are nested so that the impact head 9 of a lower projectile 8 of two nested projectiles 8 is inserted into the recess 12 in the upper projectile 8. A plurality of stacks of projectiles 8 are arranged side by side in the shell 2.

In figures 3A-3E there are shown different advantageous embodiments of the projectile 8. Thus, figure 3A shows a cylindrical projectile with a conical impact head and a conical recess. Figure 3B likewise shows a cylindrical projectile but with a dome-shaped impact head and a dome- shaped recess. Figure 3C shows a projectile with a hexagonal cross-section having a dome-shaped impact head and a dome-shaped recess. Figure 3D likewise shows a projectile with a hexagonal cross-section but having an onion-shaped impact head and an onion-shaped recess. Figure 3E shows a projectile with a square cross-section having a pyramid-shaped impact head and a pyramid-shaped recess. Also other shapes of the impact head and recess of the projectile are of course conceivable.

Claims

1. A shot cartridge (7), comprising a shell (2) with a bottom (3) and an outlet end (4) , a powder charge (5) provided in the shell at its bottom, and a multiplicity of elongate projectiles (8) consisting of a material lighter than lead and provided in the shell above the powder charge, each projectile (8) having an impact end (9) and a rearward end (10) and is asymmetrically shaped so that its centre of gravity is situated closer to the impact end (9) than the rearward end (10) , characterised in that each projectile (8) is designed with a length such that its relation between the weight and target surface at least substantially corresponds to the corresponding relation of a spherical lead bullet, whereby the striking energy of the projectile will be substantially the same as that of said lead bullet.

2. A shot cartridge according to claim 1, characterised in that each projectile (8) comprises a tapering impact head (11) at its impact end (9) and a recess (12) at its rearward end shaped at least substantially complementary to the impact head, so that the impact head of a projectile is insertable into the recess of another projectile.

3. A shot cartridge according to claim 2, characterised in that the impact head (11) and recess (12) , respectively, of each projectile (8) takes the shape of a dome.

4. A shot cartridge according to claim 2, characterised in that the impact head (11) and recess (12) , respectively, of each projectile (8) takes the shape of a pyramid.

5. An elongate projectile (8) for use in a shot cartridge (7) of the kind that contains a multiplicity of projectiles comprises an impact end (9) and a rearward end (10) , and is asymmetrically designed so that its centre of gravity is situated closer to the impact end (9) than the rearward end (10) , characterised in that it is designed with such a length that its relation between the weight and target surface at least substantially corresponds to the corresponding relation of a spherical lead bullet, whereby the striking energy of the projectile will be substantially the same as that of said lead bullet .