The development of body armour technology must be balanced with the development of ammunition technology. One of the technologies that can be undertaken to improve the performance of ammunition is to use material which is high density and high hardness in the core of the projectile, such as tungsten carbide - cobalt material (WC - 8Co). This research will analyse regarding the effects of material substitution from the Pindad’s standard steel core projectile to WC - 8Co core projectile on the performance of 5.56 × 45 calibre ammunition on ceramic material target, alumina (Al<sub>2</sub>O<sub>3</sub>). This study used experimental method by performing ballistic tests. The results showed that for Al<sub>2</sub>O<sub>3</sub> material target, projectile of WC - 8Co core produced (a) 1.2 times a depth of penetration greater than Pindad’s standard steel core projectile, (b) 2.1 times diameter of the crater bigger than Pindad’s standard steel core projectile, and (c) 1.1 times damage deeper than Pindad’s standard steel core projectile. These results showed that for Al<sub>2</sub>O<sub>3</sub> material target, the performance of projectile penetration using WC - 8Co core was better than the performance of projectile penetration using the Pindad’s standard steel core.