Breech-Loading Ordnance

All modern ordnance is now loaded at the breech instead of at the muzzle. Devices are used which not only provide a closure of great strength. but check the gas without interfering with a high speed of operation. The breech-mechanism is a combination of mechanical contrivances which close the breech, check the gas, and cover the firing apparatus. The principal devices now employed are the interrupted screw system, combined with the de Bange or cup gas-check and the horizontal wedge in combination with the AD Elevation of Breech (open). IMG:content-0609.jpg:[graphic] last. In the interrupted screw system the breech or movable block has its surface threading longitudinally divided or interrupted, while similar divisions are made in the breech thread for receiving the block. Locking devices are employed to prevent the blocks unscrewing on discharge. In the heavier ordnance a tray is hinged to the gun to support and guide the block while loading. In the wedge system the breech block moves horizontally (although a few vertical ones have been fitted) through a slot in the breech. The semi-cylindrical wedge is set up and locked by special devices. As it is more extensively used by Krupp than by any one else it is generally known as the Krupp wedge. The recoil of the gun is utilized in some devices in combination with springs for the automatic opening and closing of the breech.