Abstract: To study the effects of chamber offset on the dynamic response of small-caliber cased telescoped ammunition during engraving, we use explicit dynamic methods and couple classical internal ballistic equations while considering the combined effects of the polymer projectile cap and the barrel on the projectile. A numerical simulation model of bullet-barrel interactions during the dynamic engraving process is established. The effects of the chamber offset on the centroid offset, the in-bore declination angle, and the engraving resistance of the projectile are analyzed. The design of the projectile cap structure is optimized. Using multi-parameter synchronous measurement, the attitude measurement and accuracy experiments of the projectile are carried out, and the effectiveness of the optimization is verified. The results show that, with the increase of the chamber offset, the centroid offset, the in-bore declination angle, and the engraving resistance of the projectile all increase. Yet, the accuracy of the bullet/gun system will be reduced, and the system life and safety adversely affected. By optimizing the structure of the projectile cap, the in-bore centroid offset of the projectile can be significantly reduced, and the deviation angle and maximum engraving resistance reduced. The results can provide technical support for the design and optimization of the cased telescoped ammunition and gun system.

Key words: casedtelescopedammunition, bullet-barrelinteractions, dynamicengraving, projectilein-boreattitude, engravingresistance