A counter offensive weapon system is provided for use on a vehicle to fire upon and neutralize those launching projectiles, including RPG's, at the vehicle. A muzzle flash detected by an on-board monitoring device allows the distance and direction to the projectile launch site to be calculated so that an offensive weapon may be immediately deployed to the projectile launch site to neutralize the enemy weapon and shooter. An air burst munition is programmed to detonate just prior to reaching the measured distance to create a conical dispersion of fragments that are effective at destroying weapons such as RPG tubes. A related method for protecting a vehicle and launching counter offensive weapons is also provided.