The present study investigates the complex multiscale ballistic response of particle-filled polymer composites in an effort to link the bulk material behaviour to variations in the microstructure. The multiphase systems under investigation consist of micron-sized ceramic powders integrated within a siloxane elastomer to create flexible particulate composites. In particular, the role of the particulate phase is assessed by varying the fifiller volume fraction, material, and morphology. The experimental investigation concerns the ballistic penetration of thick targets impacted by 16-grain steel fragment simulating projectiles in the range of 200 - 900 m/s. Incident and residual velocities were measured using high-speed videography techniques. Three projectile nose geometries were considered (i.e., flat-nosed, chisel-nosed, and hemispherical) in order to note differences in the ballistic response of composites.