Short travel projectile automatically opens casing - after decrease of gas pressure which holds casing segments closed

摘要

The projectile casing comprises one or more segments which can open outwards but are first retained in their closed position by a piston contained in a cylindrical cavity terminating some distance from the projectile. When the projectile is first fired gas pressure on the rear of this piston keeps it in the forward position, so that the interlocking surfaces at the cavity keep the casing segments of the projectile closed. After a certain distance when the gas pressure drops the piston can move to the rear, assisted by a backward force, esp. that produced by the inclination of the mating faces between casing segments and piston under the centrifugal action of the segments as the projectile revolves (rotationally stabilised projectile). Used as a short-range projectile which automatically suddenly has an increased resistance in flight. This sudden increase in resistance is unaffected by such things as ambient temp. air density etc.