Apparatus for Obtaining Controlled Shot-Start Pressure in a Gun Tube

摘要

As gun tubes erode, the initial pressure needed to accelerate the projectile is reduced and hot gases escape around the projectile causing increased tube wear, decreased projectile velocity, and decreased launch stability. To reduce the variability in these parameters, several methods can be used to try to reproduce the ballistics of a good gun tube. An apparatus for obtaining a desired shot-start pressure has been designed, fabricated and successfully tested. This 'Shot-Start Projectile Apparatus' is composed of metallic and nonmetallic parts. It is fabricated to a set of drawing specifications which do not change even though the projectile is used in a gun tube which erodes from continued firing. Design characteristics, method of assembly and installation, calibration and test data are presented and discussed. Keywords: 40-mm Gun, Expandable projectile, Interior ballistics.