| 摘要 |
<p>A shotgun cartridge comprising a case having a cylindrical wall (101) and a base (102) holding a percussion ignition means (103), the cartridge including an end closure (104) and an obturating means (105, 108) having an upper face defining with the end closure (104) a shot chamber (106) containing shot (107), and having a lower face defining with the base a space containing propellant (110) in communication with the ignition means, characterised in that the end closure (104) is of fixed position and defines a fixed volume and the obturating means includes a first wad member (105) having an upper face bounding the shot chamber (106) and which is located at a fixed position within the cartridge case so its lower face determines a combustion chamber of predetermined volume, the position of the shot (107) being fixed between the upper face of the obturating means (including any spacer member) and the end closure (104). The preferred cartridge exhibits a peak pressure within the normal range (400 - 700 bars) and is characterised by an end closure (104) which opens under a negligible to weak force such that the peak pressure developed in the absence of the closure is lower by 20% or less than that developed with the closure in place. The preferred cartridge case has a cylindrical wall (101) and a base (102) formed with an extraction rim and means for receiving a cap (103), and is characterised in that the case is formed of injection moulded plastics material and in that a base outer section including the extraction rim and an adjacent wall outer surface portion is formed separately from the remainder of the case.</p> |
