IN BORE BEHAVIOUR OF LARGE CALIBRE ARMOUR PIERCING FIN STABILISED DISCARDING SABOT PROJECTILES.

The efficiency of large calibre armour piercing fin stabilised discarding sabot projectiles (APFDS) is primarily linked to their terminal ballistics performances. But other parameters, such as its accuracy and its yaw at the impact have also a large influence on the performance. These two parameters magnitude, as well as the survivability of the projectile during the launch phase are greatly affected by the interaction between the projectile and the gun, also known as the “balloting”. Nowadays, the accurate description of the rod free flight has been made possible thanks to Computational Fluid Dynamics calculations, allowing to predict the flight quality or the retardation, and back calculation of initial disturbances of an unexpectedly odd shot. But this situation is not true for the early moments of the firing sequence, i.e. the projectile inbore travel and the sabot separation. For the latter, a long way to go remains. But, in the field of projectiles in-bore behaviour, a lot of works have been performed, using different numerical methods, which allowed scientists to make significant progress. This paper describes some of the works performed in the Giat Industries Weapon and Ammunition Systems Division (DSAM), whose purpose was to understand how the interactions between the weapon and the projectile could affect its mechanical behaviour and its muzzle exit conditions.