Abstract: A twin-wire paper manufacturing machine wherein endless main and auxiliary wires are situated directly next to each other only at a convex forming surface of a forming board so that the compacting of the web takes place only between those parts of the main and auxiliary wires which assume the curvature of the forming surface. Preferably the curved forming surface forms part of a cylinder of constant radius so that the curvature of the wires during compacting of the web therebetween also is constant. By driving the wires at the same angular velocity as they travel along the forming surface, relative movement between the wires during compacting of the web therebetween is reduced to a minimum.

Abstract: A firearm which has a receiver formed with an ejection port through which the cartridge case of a spent cartridge is ejected. A bolt is situated in the receiver for movement between a forward firing position and a rear retracted position, a cartridge case being ejected when the bolt is in its rear retracted position. The bolt is also supported in the receiver for rotary movement between locked and unlocked positions. A sleeve is operatively connected to and surrounds the bolt for rotating the latter between its locked and unlocked positions, this sleeve having a length substantially less than the length of the bolt and covering part of the ejection port when the bolt is in its firing position. A cover is provided to cover that part of the port which is not covered by the sleeve when the bolt is in its firing position, and this cover responds to rearward movement of the bolt from its firing to its retracted position for uncovering the ejection port.