Mortar barrel

摘要

The mortar tube (1) has a portion of reduced outside diameter at the lower end with a male thread engaging a female thread on a cup or ground piece (2). This piece closes the end of the tube. The plain cylindrical end of the tube fits closely into the cup and the flat end of the tube (4). A cutout (5) in the inside of the end of the tube accommodates a U-section sealing ring (3) with the sides of the U (3.1) extending inward. When the mortar is fired, the gas pressure pushes the sides of the U more firmly against the end of the tube and the bottom of the cup.