A 40mm grenade from a mk19 will only penetrate 2 inches of armor. There is no way in hell you could kill a mbt with one. Maybe a hyper velocity 40mm cannon might, but a 40mm grenade, never. We had problems killing t54-55 with a m72 law rocket which had a 66mm warhead on it, so how is a warhead which can fit in the palm of your hand going to kill one? Maybe if you was on top of a building and shot straight down at a 90 degree angle but that would be almost impossible and even then only on the oldest of tanks......

Okay, that's what I thought you must have meant, because that's what I meant. Drop a bunch of 40mm grenades on a tank and sooner or later you'll disable it. Continue development of guided rounds and one day we could have one that can disable a tank with "one shot, one kill" reliability. I agree, the 40mm Mk-19 machine gun and its future derivatives are an awesome weapon system for embedded fire support at the squad/platoon level. Displacedjim