It Can Kill Within 50 Feet: Box of Armor-Piercing Grenades Was Somehow Lost Each round was capable of penetrating three inches of steel and has a “kill radius” of nearly fifty feet. A box of thirty armored-piercing grenades, which were believed to have been stolen from a train bound for Pennsylvania, was recovered in an Atlanta backyard in February 2018. The canisters of grenades had begun its journey at Blount Island, a U.S. Marine Corps depot in Jacksonville. How the ordnance of 40-millimeter rounds for the MK19 grenade launcher ended up there is anyone's guess. Still, the fact that the box of stolen grenades was so callously abandoned should be of serious concern.