| 摘要 |
In an automatic gun, the gas pressure generated by the firing of a shot shell is transmitted to the breechblock in the receiver housing by the axial sliding movement of an action bar assembly mounted outside the gunbarrel or the cartridge magazing tube for releasing the breechblock. The action bar assembly includes action bars slidably mounted coaxially with each other and an adjusting spring for arresting the contraction of the span between the stem bodies. A cylinder is fixed to the gunbarrel for receiving the gas pressure from it. The forward end of the action bar assembly extends into the cylinder, while the rearward end passes through a guide hole in the receiver into contact with the front surface of the breechblock. The rearward end has a stopper for restricting the axial movement of the action bar assembly to a predetermined length. A supporting mechanism serves to arrest the rotation of the gunbarrel and the fore-arm by engaging a projection of a predetermined shape, provided at the forward end of the receiver, with cutout portions in the outer periphery of the gunbarrel and the fore-arm. |
