초록 ▼

A wad for a projectile cartridge comprises a holder for holding a projectile, such as a plurality of shot, a charge barrier, and a support for mounting the holder to the barrier. The wad is unitary and is formed from a biodegradable plastic material. The barrier is preferably compressible, and more

A wad for a projectile cartridge comprises a holder for holding a projectile, such as a plurality of shot, a charge barrier, and a support for mounting the holder to the barrier. The wad is unitary and is formed from a biodegradable plastic material. The barrier is preferably compressible, and more preferably substantially more compressible than the support. The wad has a first moisture content and is adapted to be conditioned, prior to employment in a projectile cartridge, to have a second moisture content. After conditioning, the weight of the wad may be increased by up to 19%, or the size of the wad maybe increased in at least one dimension by up to 6%. A projectile cartridge employing the wad, and a method of making the wad and the projectile cartridge are also disclosed, together with tools for making the wad and sleeve.

대표청구항 ▼

The invention claimed is: 1. A wad for a projectile cartridge, the wad comprising: a holder for holding a projectile; a charge barrier; and a support for mounting the holder to the barrier, wherein the wad is unitary and is formed from a biodegradable plastic material, and wherein the wad has a fir

The invention claimed is: 1. A wad for a projectile cartridge, the wad comprising: a holder for holding a projectile; a charge barrier; and a support for mounting the holder to the barrier, wherein the wad is unitary and is formed from a biodegradable plastic material, and wherein the wad has a first moisture content and is conditioned, prior to employment in a projectile cartridge, to have a second moisture content greater than the first moisture content. 2. The wad of claim 1 wherein the barrier is compressible or is substantially more compressible than the support. 3. The wad of claim 1 wherein the barrier comprises a base coupled to the support and a flexible cylindrical sidewall extending from the base and defining an opening distal from the base. 4. The wad of claim 1 wherein the first moisture content is <0.5% by weight of the wad and the second moisture content is <20% by weight of the wad. 5. The wad of claim 1 wherein when the wad has the second moisture content, it is greater in size in at least one dimension by up to 6% than when it has the first moisture content. 6. The wad of claim 1 wherein when the wad has the second moisture content, it is greater in size in at least one dimension by about 2% than when it has the first moisture content. 7. The wad of claim 1 wherein the first moisture content is substantially 0% by wad weight. 8. The wad of claim 1 wherein the plastic comprises polyvinyl alcohol (PVA) and plasticiser. 9. The wad of claim 8 wherein the plasticiser comprises glycerine and/or propylene glycol. 10. The wad of claim 1 wherein the plastic comprises, by weight, 40 to 95% of PVA and 5 to 20% plasticiser. 11. The wad of claim 1 wherein the plastic comprises, by weight, 0 to 49% filler and 0 to 5% binder. 12. The wad of claim 11 wherein the filler comprises calcium carbonate and the binder comprises 0-1% calcium stearate, and/or 0-1% zinc stearate, and/or 0-2% stearamide. 13. The wad of claim 1 wherein the plastic comprises, by weight: 0-2% of pigment, preferably titanium dioxide. 14. The wad of claim 1 wherein the plastic comprises, by weight: 40 to 95% of PVA; 5 to 20% of glycerine and/or propylene glycol as plasticiser; 0 to 49% of calcium carbonate as filler; 0-1% calcium stearate, and/or 0-1% zinc stearate, and/or 0-2% stearamide as binder; and 0-2% of titanium dioxide as pigment, the total amount being 100%. 15. The wad of claim 1 wherein the plastic comprises, by weight: 0 to 67% PVA; 0 to 30% calcium carbonate; 15 to 17% glycerine and/or propylene glycol; 0 to 1% titanium dioxide; and 0 to 0.3% calcium stearate, and/or 0 to 0.2% zinc stearate, and/or 0-1.5% stearamide, the total amount being 100%. 16. The wad of claim 1 wherein the support comprises a partly hollow portion having a structural element therein for maintaining the structural integrity of the partly hollow portion. 17. The wad of claim 16 wherein structural element comprises a rib which lies on a plane substantially parallel to a longitudinal axis of the wad. 18. The wad of claim 17 wherein the partly hollow portion comprises a cylinder having a longitudinal axis across the longitudinal axis of the wad, and wherein the rib is internal of the cylinder. 19. The wad of claim 17 comprising a second rib, each rib lying on a respective plane substantially parallel to the longitudinal axis of the wad, and wherein the planes on which each of the ribs lies intersect each other. 20. The wad of claim 1 wherein the support comprises a solid post. 21. The wad of claim 1 wherein the projectile comprises a plurality of shot and the holder is configured to radially constrain the shot. 22. The wad of claim 1 wherein the projectile comprises a slug. 23. The wad of claim 1 wherein the holder comprises a cup. 24. The wad of claim 23 wherein the cup comprises a base and a cylindrical sidewall extending from the base, the sidewall comprising longitudinally directed slots extending through a distal end of the sidewall. 25. The wad of claim 1 being cold water soluble. 26. A projectile cartridge comprising: a sleeve having a base at one end and an opening at another end; a unitary wad within the sleeve comprising a holder for holding a projectile, a charge barrier, and a support for mounting the holder to the barrier, a charge material in the sleeve between the base and charge barrier; a primer in the base for igniting the charge material; a projectile in the holder; and a capping element for closing the opening end of the sleeve, wherein the wad is formed from a biodegradable plastic material, and wherein the wad has a first moisture content and is conditioned, prior to employment in a projectile cartridge, to have a second moisture content greater than the first moisture content. 27. A wad for a projectile cartridge, the wad comprising: a holder for holding a projectile; a charge barrier; and a support for mounting the holder to the barrier, wherein the wad is unitary and is formed from a biodegradable plastic material, and further wherein the plastic comprises, by weight; 40 to 95% of PVA; 5 to 20% of glycerine and/or propylene glycol as plasticiser; 0 to 49% of calcium carbonate as filler; 0-1% calcium stearate, and/or 0-1% zinc stearate, and/or 0-2% stearamide as binder; and 0-2% of titanium dioxide as pigment, the total amount being 100%. 28. A wad for a projectile cartridge, the wad comprising: a holder for holding a projectile; a charge barrier; and a support for mounting the holder to the barrier, wherein the wad is unitary and is formed from a biodegradable plastic material, and further wherein the plastic comprises, by weight: 0 to 67% PVA; 0 to 30% calcium carbonate; 15 to 17% glycerine and/or propylene glycol; 0 to 1% titanium dioxide; and 0 to 0.3% calcium stearate, and/or 0 to 0.2% zinc stearate, and/or 0-1.5% stearamide, the total amount being 100%.