The U.S. military recently spent nearly 3/4 of a million dollars on paint ball guns and sent them to Afghanistan. An M16 is not the best tool to simply disable someone. Load a 10% pepper ball into a toy paint ball gun, and that will stop anyone, including intruders on your boat. Put in a "glass breaker" ball and an intruder will realize he made a bad choice of a boat to invade or steal from. There are a lot of cool ideas in this shop, in a mall, in S. Africa to ward off thieves and lightly armed pirates from a sailboat.