A WAD FOR A SHOTGUN CARTRIDGE

Abstract

A wad for a shotgun cartridge is provided, the wad comprising: a wall defining a cavity therein for holding a projectile, the wall having a first end having an opening and a second end; a base member having a first end and a second end, the base member being disposed at the first end of the wall and closing the opening at the first end of the wall; wherein the base member is moveable relative to the wall between a first position and a second position, movement of the base member from the first position to the second position expanding a portion of the wall adjacent the first end of the wall. A shotgun cartridge is provided, the cartridge comprising: a head comprising a primer; a sleeve extending from the head having a distal end; a charge of explosive powder disposed within the head adjacent the primer; a wad as provided, the wad disposed within the sleeve on the opposite side of the power with the base member towards the head and the second end of the wall towards the distal end of the sleeve; and a projectile disposed within the cavity of the wad.

Description

The present invention relates to a wad for a shotgun cartridge. The invention further relates to shotgun cartridges comprising the wad.

Generally, a shotgun cartridge is composed of five components, namely: a primer, gun powder, a wad, shot and a case. Modern cases are usually made of plastic and have a brass head at one end. The other end is closed by crimping the end of the plastic so that it folds down onto itself to close the case. This closure is widely referred to as a ‘folded crimp’. Located within the case are the other four components. The primer is located in the centre of the brass head of the cartridge. Adjacent the primer and inside the brass head is located the gun powder. Adjacent the gun powder is a wad. The wad is usually made of fibre or plastic and creates a seal within the cartridge so that explosive gases generated by ignition of the powder do not dissipate, for example by blowing through the shot, and the full pressure of the gases builds up below the wad to propel the wad and shot out of the cartridge with the maximum force. The wad also creates a barrier between the shot and the powder so that they do not mix. The shot generally comprises a plurality of small round metal pellets. The pellets were traditionally lead pellets. However, non-lead alternatives are now also used.

During use of the cartridge, with the cartridge loaded into a shotgun, when the shotgun is fired, the primer is hit by the firing pin of the shotgun. This impact causes a chemical reaction to occur in the primer, which produces heat. This heat then ignites the gun powder. Ignition of the powder creates explosive gases, which in turn create the required pressure to propel the wad and shot forwards out of the cartridge case and to exit the barrel of the shotgun towards the target. Generally, due to air resistance on the wad and the relatively light weight of the wad, the wad will separate from the shot and while the shot continues to head towards the target, the wad will fall to the ground some distance from where the gun is fired. This is typically around 20 to 40 metres from where the gun is fired.

An example of a wad for shotgun or rifle cartridges is disclosed in EP 0196262 A2.

FR 2343219 A1 and FR 2308901 A2 similarly disclose wads which fit between the charge of powder and the shot in a hunting gun cartridge.

Further examples of firearm shot cartridges are described in GB 1115400 A.

Currently, most wads are in the form of a plastic, or in some cases biodegradable, cup within which the shot is held in the cartridge.

For example, GB 2586909 B discloses a wad for a shotgun cartridge comprising a cup-shaped member.

However, cup-shaped wads according to the prior art suffer from certain disadvantages. In particular, as the wad is expelled from the case and travels down the barrel of the shotgun, the pressurised gases may escape by dissipating between the wad and the barrel. This causes the gas pressure behind the wad to drop, resulting in a reduction in the power and range of the shotgun.

Attempts have been made to provide shotgun cartridges that reduce loss of pressurised gas when fired.

GB 1094817 A, for example, discloses undershot cartridge wads which aim to provide sealing of combustion gases.

In a similar fashion, GB 191309783 A relates to sporting cartridge cases, in which a thick cup is inserted within the cartridge case, the said cup having a base corrugation to ensure a better seal against the escape of gases of explosion.

However, there remains a need for an improved shotgun cartridge, which overcomes the drawbacks of existing cartridge designs. In particular, it would be advantageous to provide a shotgun cartridge that exhibits a reduced loss of pressurised gas when fired, thereby increasing the efficiency of the cartridge when fired.

In accordance with a first aspect of the present invention, there is provided a wad for a shotgun cartridge, the wad comprising:

• • a wall defining a cavity therein for holding a projectile, the wall having a first end having an opening and a second end;
  • a base member having a first end and a second end, the base member being disposed at the first end of the wall and closing the opening at the first end of the wall;
  • wherein the base member is moveable relative to the wall between a first position and a second position, movement of the base member from the first position to the second position expanding a portion of the wall adjacent the first end of the wall.

The wad of the present invention comprises a wall defining a cavity. In use within a shotgun cartridge, the cavity is used to hold the shotgun pellets to be discharged from the shotgun when fired. The wall has a first end and a second end. In use, the first end of the wall is oriented within the cartridge towards the head of the cartridge and the second end of the wall is oriented towards, more preferably at, the end of the cartridge through which the pellets emerge when fired. The first end of the wall comprises an opening such that the cavity is open at the first end. The second end of the wall may also be open.

The wall may have any suitable form. Most preferably, the wall is generally cylindrical.

The wall may comprise one or more slits therein, more preferably one or more longitudinal slits. The one or more slits preferably extend from the second end of the wall.

The wall may be formed from any suitable material. Suitable materials are known in the art. Preferably, the wall is formed from a biodegradable material, as discussed in more detail hereinbelow. Preferably, the base member is formed from a biodegradable material. In one particularly preferred embodiment, both the wall and the base member are formed from biodegradable materials.

The wall defines a cavity therein. In use of the wad within a cartridge, the cavity holds a projectile. In many embodiments, the cavity holds a plurality of projectiles or shot.

The wad further comprises a base member. The base member is disposed at the first end of the wall and closes the opening in the wall at the first end. By closing the opening in the first end of the wall, the base member seals the cavity at the first end of the wall. The base member has a first end and a second end and is oriented such that the first end is towards the first end of the wall.

The base member is moveable with respect to the wall. In particular, the base member is moveable from a first position to a second position. The movement of the base member from the first position to the second position is caused when a cartridge containing the wad is loaded into a shotgun and the gun is fired. The movement of the base member from the first position to the second position causes the base member to expand the portion of the wall of adjacent the first end of the wall, that is to increase a diameter of the first end portion of the wall. In this way, the first end portion of the wall is forced radially outwards and forms an improved seal with the inner surface of the barrel of the shotgun along which the wad is moving. This in turn reduces or eliminates the escape of the pressurised gases past the wad along the barrel, increasing the efficiency of the conversion of the energy of the combustion of the gun powder into kinetic energy of the wad and its contents along the barrel of the shotgun. This in turn increases the range of the shotgun.

The base member may have any suitable shape, allowing it to perform the aforementioned function. Preferably, the base member is substantially disc-shaped, with the first end and the second end both being circular.

As noted above, the base member closes the opening at the first end of the wall. In moving to the second position, the base member expands the first end portion of the wall of the first member. To do this, in moving from the first position to the second position, the base member moves towards the second end of the wall, which is distal of the base member. Most preferably, in the second position, the first end of the base member lies within the cavity. In this way, when the shotgun is fired, the base member is driven into the cavity at the first end of the wall by the explosion of the gun powder, resulting in the first end portion of the wall being expanded radially outwards.

In the second position of the base member, the second end of the base member may lie inside the cavity within the wall. More preferably, in the second position, the second end of the base member lies outside the cavity.

Preferably, in the first position, the first end of the base member lies within the cavity within the wall.

Preferably, in the first position, the second end of the base member lies outside the cavity within the wall.

The diameter of the first end of the base member is preferably no greater than the diameter of the cavity at the first end of the wall. In this way, the first end of the base member is able to enter the cavity when the base member moves from the first position to the second position. More preferably, the first end of the base member has a diameter that is less than the diameter of the cavity at the first end of the wall.

Preferably, the second end of the base member has a diameter that is at least the same, more preferably greater than the diameter of the cavity at the first end of the wall, when the wall is in the non-expanded state. In one embodiment, the second end of the base member has a diameter that is greater than the diameter of the cavity at the first end of the wall, when the wall is in the expanded state.

In one embodiment, the diameter of the first end of the base member is the same or greater than the diameter of the second end of the base member. In a preferred embodiment, the diameter of the first end of the base member is less than the diameter of the second end of the base member. In this way, the diameter of the base member increases in the direction from the first end to the second. Preferably, the base member comprises an outer surface extending between the first end and the second end, the diameter of a least a portion of the outer surface increasing in the direction from the first end to the second end of the base member. The increase in diameter may be stepwise or continuous.

In one preferred embodiment, the diameter of at least a portion of the outer surface of the base member increases continuously. In other words, the outer surface comprises a taper. In one preferred embodiment, the outer surface comprises a tapered portion extending from the second end towards the first end of the base member. In one embodiment, the base member is frustoconical, that is the outer surface tapers, such that its diameter decreases, from the second end to the first end of the base member.

As described hereinbefore, under the action of the cartridge being fired within the barrel of a shotgun, the base member is caused to move from the first position to the second position. In one embodiment, movement of the base member from the first position to the second position is limited. This prevents the base member entering too far into the cavity within the wall. The movement of the base member relative to the wall may be limited by providing one or more protrusions on the base member and/or the wall which prevent the base member moving beyond the desired second position. In one embodiment, the base member comprises a protrusion which engages with the wall when the base member reaches the second position and thereby limits further movement of the base member relative to the wall. Preferably, the protrusion is at or adjacent the second end of the base member. Preferably, the protrusion engages with the first end of the wall when the base member is in the second position. More preferably, when the base member is in the first position, the protrusion is spaced apart from the wall, movement of the base member from the first position to the second position bringing the protrusion into contact with the first end of the wall.

In one preferred embodiment, the protrusion is in the form of a flange at or adjacent the second end of the base member, the flange extending radially outwards. The flange preferably has a diameter that is larger than the diameter of the cavity at the first end of the wall, when the wall is in the non-expanded state. In one embodiment, the diameter of the flange is substantially the same as the outer diameter of the wall in the non-expanded state. Preferably, the diameter of the flange is greater than the diameter of the cavity at the first end of the wall, when the wall is in the expanded state. In use, the base member is forced into the cavity within the wall, expanding the first end portion of the wall, until the flange abuts the first end of the wall.

In a further embodiment, the wall comprises a protrusion which engages with the base member when the base member reaches the second position and thereby limits further movement of the base member relative to the wall. Preferably, the protrusion is formed on the inner surface of the wall, within the cavity. Preferably, the protrusion engages with the first end of the base member when the base member is in the second position. More preferably, when the base member is in the first position, the protrusion is spaced apart from the base member, movement of the base member from the first position to the second position bringing the protrusion into contact with the first end of the base member.

In one embodiment, the wad further comprises a separation member located in the cavity within the wall adjacent the first end of the wall and the base member. Suitable materials for forming the separation member are known in the art. Preferably, the separation member is formed from a biodegradable material.

As noted above, the wall is preferably formed from a biodegradable material, more particularly a first biodegradable material. As noted above, the base member is preferably also formed from a biodegradable material, more particularly a second biodegradable material. The separation member, if employed, may also be formed from a biodegradable material, more particularly a third biodegradable material.

The first, second and third biodegradable materials may be the same or may be different.

Preferably, at least one of the first, second, and third biodegradable materials is a fibrous material, more preferably a natural fibrous material and still more preferably is a natural organic fibrous material. Preferably, at least one of the first, second, and third biodegradable materials is formed from at least one of a cellulose based fibrous material and a protein based fibrous material.

Additionally or alternatively, at least one of the first, second, and third biodegradable materials comprises at least one of a compostable material and a water soluble material. In this manner, at least one of the wall, base member, and the separation member, if used, are formed from a compostable material and/or a water soluble material.

In one embodiment, at least one of the wall, base member, and the separation member, if used, are formed from a cellulose based fibrous material that may be plant based, for example wood based.

Preferably, at least one of the wall, base member, and the separation member, if used, are formed at least in part from a pulp material, and more preferably at least one of the wall, base member, and the separation member, if used, are formed at least in part from card or cardboard.

Alternatively, at least one of the wall, base member, and the separation member, if used, are formed at least in part from a felt material. For example, the felt material may be formed from one or more of wool, hair, fur and cellulose fibres.

Where the at least one of the first, second, and third biodegradable materials comprises a protein-based fibrous material, the protein-based fibrous material may comprise at least one of wool, hair and fur.

Preferably, the wall comprises a fabric material. The fabric material may be woven or knitted, more preferably woven. The fabric material may be formed from a biodegradable material, which is preferably a naturally occurring material. For example, the fabric material may be formed from a plant-based fibrous material or from a protein-based fibrous material. Protein-based fibrous materials typically come from animals, such as mammals or insects. The fabric material may be formed from combinations of different plant-based fibrous materials, combinations of different protein-based materials or combinations of different plant-based and protein-based fibrous materials. Examples of plant-based fibrous materials for the fabric material include cotton, hemp, flax and jute. Examples of protein-based fibrous materials for the fabric material include wool, silk and hair.

The wall preferably comprises the fabric material and at least one other material. The other material may be, for example, a material formed from a pulp, such as card. The fabric material may be incorporated into the wall, such as, by being laminated onto the at least one other material. For example, the fabric material may be incorporated into the wall by being laminated onto the at least one other material such that it forms an outer layer of the wall on the outside or inside of the wall or laminated between layers of the at least one other material so that it is within the wall.

Alternatively, the fabric material may be incorporated into the wall by being entrapped or embedded within the at least one other material. This may be during a manufacturing process, for example, during a moulding process.

In a further alternative, the wall may comprise a number of layers of fabric material and a number of layers of at least one other material with at least one of the layers of the at least one other material having a fabric material entrapped or embedded therewithin,

The fabric material may be incorporated into only a portion of the wall or may extend throughout the wall. Preferably, the fabric material extends along the full length of the wall from the first end to the second end thereof.

An advantage of the wall comprising a fabric material is that the fabric material assists in improving the structural strength of the wall. This reduces the risk of the wall disintegrating when a shotgun cartridge including the wad is fired from a shot gun.

Additionally or alternatively, the wall may be formed from at least one of a compostable material and a water soluble material.

The wall may be formed by any suitable process. In a preferred embodiment, the wall may be formed by moulding.

The base member may be formed from a compressed fibrous material. The compressed fibrous material may be a compressed protein based fibrous material, such as wool, hair or fur. Protein-based fibrous materials typically come from animals, such as mammals or insects. The compressed fibrous material may additionally or alternatively include plant based fibres such as a cellulose based fibrous material, for example wood based fibrous material, cotton or flax or a compressed pulp material. Additionally or alternatively, the base member may be formed from at least one of a compostable material and a water soluble material.

The base member may be formed by any suitable process. In a preferred embodiment, the base member may be formed by moulding.

The separation member may be formed from a compressed fibrous material. The compressed fibrous material may be a compressed protein based fibrous material, such as wool, hair or fur. In one example, the fibrous material could be in the form of a felt, such as a felt formed from one or more of wool, hair, fur and cellulose fibre. Alternatively, the compressed fibrous material may be a compressed cellulose based fibrous material, such as cotton or flax or a compressed pulp material. Additionally or alternatively, the separation member may be formed from at least one of a compostable material and a water soluble material.

The separation member may be formed by any suitable process. In a preferred embodiment, the separation member may be formed by moulding.

In a further aspect, the present invention provides a shotgun cartridge comprising a wad as hereinbefore described.

In particular, the shotgun cartridge may comprise:

• • a head comprising a primer;
  • a sleeve extending from the head having a distal end;
  • a charge of explosive powder disposed within the head adjacent the primer;
  • a wad as hereinbefore described, the wad disposed within the sleeve on the opposite side of the powder to the head, with the base member towards the head and the second end of the wall towards the distal end of the sleeve; and
  • a projectile disposed within the cavity of the wad.

In a still further aspect, the present invention provides a method of operating a shotgun, the method comprising:

• • loading a cartridge as hereinbefore described into the chamber of the shotgun; and
  • firing the shotgun.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a case for a shotgun cartridge;

FIG. 2 is a first perspective view of a wad for a shotgun cartridge according to a first embodiment;

FIG. 3 is a second perspective view of the wad of FIG. 2;

FIG. 4 is a longitudinal cross-sectional view of the wad of FIGS. 2 and 3;

FIG. 5 is a longitudinal cross-sectional view of a first embodiment of a shotgun cartridge comprising a wad having the general configuration of the wad of FIGS. 2 to 4;

FIG. 6 is a perspective view of a wad for a shotgun cartridge according to a second embodiment;

FIG. 7 is a longitudinal cross-sectional view of a second embodiment of a shotgun cartridge comprising a wad having the general configuration of the wad of FIG. 6; and

FIG. 8 is a longitudinal cross-sectional view of a third embodiment of a shotgun cartridge comprising a wad having the general configuration of the wad of FIG. 6.

FIG. 1 shows a case for a shotgun cartridge, indicated generally as 2. The case 2 comprises a generally cylindrical sleeve 4, and a metal head 6. The sleeve 4 may be formed from plastic. Preferably the head 6 is formed from brass. The head 6 has a base 8 and a generally cylindrical side wall 10 extending from the base, into which one end portion of the sleeve 4 extends. Hence, one end of the sleeve 4 is effectively closed by the base 8 of the head 6. The second end of the sleeve 4 may be closed by crimping once the remaining components of the shotgun cartridge are assembled within the case 2, as is known in the art.

FIGS. 2 and 3 show perspective views of a first embodiment of a wad of the present invention, indicated generally as 20. FIG. 4 shows a longitudinal cross-sectional view of the wad 4 of FIGS. 2 and 3. The wad 20 comprises a generally cylindrical wall 22 extending about a central longitudinal axis A and defining a cavity 24 therein. The wall 22 has a first end 26 and a second end 28. The first end 26 of the wall 22 is open. The second end 28 of the wall 22 is open for receiving further components of the shotgun cartridge into the cavity 24, as described in more detail hereinbelow.

The wad 20 further comprises a generally disc-shaped base member 40 disposed at the first end 26 of the wall 22. The base member 40 closes the first end 26 of the wall 22. The base member 40 has a generally circular first end 42 and a generally circular second end 44. An outer surface 46 extends between the first end 42 and the second end 44 of the base member 40. In the embodiment shown in FIGS. 2, 3 and 4 the first end 42 of the base member 40 has a diameter d₁, while the second end 44 has a diameter d₂, with d₁ being less than d₂. The outer surface 46 is formed with a continuous taper extending from a flange 48, the flange extending radially outwards from the second end 44, to the first end 42.

FIG. 5 shows a longitudinal cross-sectional view of a first embodiment of a shotgun cartridge, indicated generally as 50. The cartridge 50 comprises a case 52 having the same general configuration as the case 2 shown in FIG. 1 and described hereinbefore. Thus, the case 52 comprises a generally cylindrical sleeve 4, and a metal head 6. The head 6 has a base 8 and a generally cylindrical side wall 10. A primer 54 is disposed in an aperture in the centre of the base 8 of the head 6. A charge of gun powder 56 is located adjacent the base 8 in contact with the primer 54.

A wad 60 having the general configuration of the wad of FIGS. 2 to 4 is disposed concentrically within the sleeve 4 of the cartridge 50. The wad 60 has a generally cylindrical wall 62 defining a cylindrical cavity 64 and has a first end 66 and a second end 68. A base member 70 is disposed at the first end 66 of the wall 62 and closes the opening at the first end. The wad 60 is configured so that the external diameter of the wall 62 is the same as or slightly less than the internal diameter of the sleeve 4 of the case 52. This enables the wad 60 to fit inside the sleeve 4, as shown in FIG. 5.

The base member 70 of this embodiment comprises a generally circular first end 72 and a generally circular second end 74. An outer surface 76 extends between the first end 72 and the second end 74 of the base member 70. In the embodiment shown in FIG. 5, the first end 72 of the base member 70 has a first diameter, while the second end 74 has a second diameter, with the first diameter being less than the second diameter. The outer surface 76 is formed with a continuous taper extending from a flange 78, the flange extending radially outwards from the second end 74, to the first end 72.

To assemble the cartridge 50, the wad 60 is inserted into the open end of the sleeve 4 of the case 52 and the wad is pressed down into the case so that it rests on the gun powder 56, as shown in FIG. 5.

The wad 60 may comprise a separation member 90, as shown in FIG. 5. The separation member 90 is optionally included in the wad 60 to separate the shot from the base member 70. For example, when using shot made from higher density metals or alloys, such as lead, which take up a smaller amount of space per unit weight, it may be desirable to include a separation member 90 in the wad 60. However, when using shot made from lower density metals or alloys, such as steel, which take up a larger amount of space within the wad 60 per unit weight, the separation member 90 may be omitted, for example as shown in the wad of FIG. 4.

As shown in FIG. 5, the separation member 90 is disposed inside the wad 60 so that the separation member 90 is located at the bottom of the wad 60 adjacent the base member 70. The separation member 90 effectively forms a plug in the wad 60. The separation member 90 is typically a push fit or friction fit inside the wall 62 of the wad 60.

Shot 92 is disposed in the wad 60 above the separation member 90. The case 52 is closed by crimping the open end of the sleeve 4 over the second end 68 of the wall 62 of the wad 60 and across the top of the shot 92 to form a folded crimp closure 94. Any suitable folded crimp could be used, such as six or eight star folded crimp.

In use the shotgun cartridge 50 is used in the same way as a conventional shotgun cartridge. When the shotgun is fired, the firing pin of the shotgun strikes the primer 54 which causes ignition of the gun powder 56. Ignition of the gun powder 56 generates explosive gases that compress between the base 8 of the head 6 and the base member 70 of the wad 60. These gases create the required pressure to propel the wad 60 (comprising the base member 70 and the wall 62), together with the separation member 90 and the shot 92 out of the cartridge 50 by pushing the wad 60 through the folded crimp 94 and out of the barrel of the gun towards a target.

The base member 70 is shown in the first position in FIG. 5, that is the position before the cartridge is loaded into the chamber of a shotgun and the gun is fired. As can be seen, in the first position, the base member 70 is positioned to have the flange 78 spaced apart from the first end 66 of the wall 62. In the first position, the first end 72 of the base member 70 lies within the cavity 64. When the gun is fired, the action of the exploding gun powder is to force the base member 70 from the first position, shown in FIG. 5, to the second position, in which the flange 78 is in contact with the first end 66 of the wall 62. The movement of the base member 70 causes the tapered portion of the outer surface 76 to bear against the wall 62 and expand the portion of the wall in the region of the first end 66. The expansion of the wall 62 by the base member 70 of the wad 60 results in the wad 60 forming an improved seal with the inner surface of the barrel of the gun, as the wad and its contents pass along the barrel. This in turn increases the efficiency of the gun, in particular the range of the gun.

An advantage of the separation member 90 is that it helps to provide additional structural strength or support to the wad 60, particularly at the first end 66 of the wall 62. The separation member 90 also acts as a barrier between the base member 70 of the wad 60 and the shot 92 located in the cavity 64 above the separation member 90. The separation member 90 can also provide some shock absorption between the explosive gases generated by the powder 56 in the cartridge 52 and the shot 92.

After exiting the barrel of the gun, the shot 92 continues to fly towards the target but air resistance on the wad 60, comprising the base member 70 and wall 62 (and separation member 90, if present), and the relatively light weight of the wad 60 results in the wad 60 separating from the shot 92 and falling to the ground some distance from the shotgun.

FIG. 6 shows a second embodiment of a wad, indicated generally as 102. As the wad 102 is very similar to the wad shown in FIGS. 2 to 4, the same reference numerals have been used in FIG. 8 to indicate the parts of the wad 102 that are the same as the wad of FIGS. 2 to 4. In the wad 102, the wall 22 has four slots 104 extending from the second end 28 of the wall 22. The slots 104 extend substantially parallel to the axis A of the wad 102.

FIG. 7 shows a longitudinal cross-sectional view of a shotgun cartridge, indicated generally at 120, which is identical to the shotgun cartridge 50 of FIG. 5, except that the wall 62 of the wad 60 has slots 122 extending from the second end 68, in the same manner as in the wad 102 of FIG. 6. Accordingly, the same reference numerals have been used in FIG. 7 to indicate the parts of the shotgun cartridge 120 that are the same as the shotgun cartridge 50 of FIG. 5. Preferably, the size of the slots 122 is such that the width of each slot is less than the diameter of the shot 92. Typically, the slots 122 have a width of approximately 1 mm. This minimises the risk of the shot 92 passing through the slots 122.

In the wad 60 of FIG. 7, the slots 122 extend from the second end 68 of the wall 62 to approximately adjacent the upper end of the separation member 90, that is, the end of the separation member 90 that is opposite the base member 70 of the wad 60. However, slots of a different length could be used as desired. It is also possible that the slots 122 may not necessarily extend all the way to the second end 68 of the wall 62.

An advantage of providing the slots 122 in the wall 62 is that the slots 122 permit the wall 62 to compress if necessary, to facilitate easier exit of the wad 60, containing the separation member 90 and the shot 92 from the case 52 and the barrel of the shotgun, and particularly through the choke at the end of the barrel.

FIG. 8 shows a third embodiment of a shotgun cartridge, generally indicated as 202. The shotgun cartridge 202 is identical to the shotgun cartridge shown in FIG. 7, except for the addition of a barrier member 204 between the base member 70 of the wad 60 and the gun powder 56. Accordingly, the same reference numerals have been used in FIG. 8 to indicate the parts of the shotgun cartridge 202 that are the same as the shotgun cartridge of FIG. 7.

The barrier member 204 is approximately disc shaped and extends across the internal diameter of the sleeve 4. Hence the barrier member 204 separates the powder 56 from the base member 70 of the wad 60 and helps to minimise or prevent contact between the powder 56 and the wad 60.

The advantage of the barrier member 204 is that it helps to minimise the impact of the explosive gases, created by ignition of the powder 56, on the base member 70 of the wad 60 by providing a barrier which helps to protect the base member 70.

In use, the barrier member 204 is propelled out of the case 52 and the barrel of the gun together with the wad 60 (comprising the wall 62 and the base member 70), the separation member 90, and shot 92, in a similar manner to how the wad 60 and shot 92 are propelled out of the shotgun cartridge 50, as described above.

Claims

1. A wad for a shotgun cartridge, the wad comprising: a wall defining a cavity therein for holding a projectile, the wall having a first end having an opening and a second end;a base member having a first end and a second end, the base member being disposed at the first end of the wall and closing the opening at the first end of the wall;wherein the base member is moveable relative to the wall between a first position and a second position, movement of the base member from the first position to the second position expanding a portion of the wall adjacent the first end of the wall.

2. The wad according to claim 1, wherein, in the second position, the first end of the base member is disposed within the cavity.

3-18. (canceled)

19. The wad according to claim 1, wherein, in the first position, the first end of the base member is disposed within the cavity.

20. The wad according to claim 1, wherein, in the first position, the second end of the base member is disposed outside the cavity.

21. The wad according to claim 1, wherein the first end of the base member has a diameter that is no greater than a diameter of the cavity at the first end of the wall.

22. The wad according to claim 1, wherein the diameter of the first end of the base member is less than the diameter of the second end of the base member.

23. The wad according to claim 1, wherein the second end of the base member has a diameter that is greater than a diameter of the cavity at the first end of the wall.

24. The wad according to claim 1, wherein the base member comprises an outer surface extending between the first end and the second end, the diameter of at least a portion of the outer surface increasing in the direction from the first end to the second end of the base member.

25. The wad according to claim 24, wherein the diameter of at least a portion of the outer surface increases stepwise or continuously.

26. The wad according to claim 24, wherein the outer surface comprises a tapered portion extending from the second end towards the first end of the base member.

27. The wad according to claim 1, wherein the movement of the base member relative to the wall is limited.

28. The wad according to claim 27, wherein the base member comprises a protrusion, the protrusion engaging with the wall when the base member is in the second position, thereby limiting movement of the base member relative to the wall.

29. The wad according to claim 28, wherein the protrusion is spaced from the wall when the base member is in the first position.

30. The wad according to claim 28, wherein the protrusion is at the second end of the base member and engages with the end of the wall when the base member is in the second position.

31. The wad according to claim 28, wherein the protrusion comprises a radially outward extending flange.

32. The wad according to claim 31, wherein the flange has a diameter that is substantially the same as the outer diameter of the first end of the wall.

33. A cartridge comprising: a head comprising a primer;a sleeve extending from the head having a distal end;a charge of explosive powder disposed within the head adjacent the primer,a wad according to claim 1, the wad disposed within the sleeve on the opposite side of the power with the base member towards the head and the second end of the wall towards the distal end of the sleeve; anda projectile disposed within the cavity of the wad.

34. A method of operating a shotgun, the method comprising: loading a cartridge according to claim 33 into the chamber of the shotgun; andfiring the shotgun.