Abstract: In modern counter - terrorism operations, rapid indoor entry often requires breaching doors. Door breaching rounds can destroy locks or chains to facilitate this. However, traditional shotgun-fired breaching rounds may cause collateral damage with their steel shot and fragments. So, this paper presents a new LCD (Low Collateral Damage) breaching round. It uses an internally ribbed porous thin-walled non-metallic cylinder as the carrier and is filled with high density metal powder. This structure ensures stability during firing, boosting penetration. After breaching, the metal powder quickly loses kinetic energy, reducing collateral damage. Ballistic tests and numerical simulations were done to study the breaching and collateral damage of this new round on steel targets. The effects of powder material, initial kinetic energy, and internal ribs were examined. The penetration and energy-absorption mechanisms of the porous cylinder with metal powder were analyzed. Results showed that a 2-order ribbed breaching round needs less initial kinetic energy and causes non-lethal collateral damage. This round, with its internal support, maintains stability during firing, enhancing penetration. After breaching, the metal powder's kinetic energy rapidly diminishes, lowering collateral damage. The study found that the 2-order ribbed round is efficient, needing less initial kinetic energy and causing non-lethal damage.