Laminated composite armors provide significant advantages to the defense systems when considering both the mobility and energy consumption. Among them, alumina faced laminated composite systems have been considered as strong candidates due to their relatively low cost and availability. In this study, the ballistic response of alumina/4340 steel laminated composites was investigated under the impact of 7.62 mm armor piercing (AP) projectiles. The influence of the mechanical properties of the steel backing layer and the areal density on the ballistic performance of these composites was examined. Experimental results showed that the best ballistic protection was found for the composites having the steel backing layer of 40 or 50 HRC (Hardness Rockwell C).