I knew somehow they would get something to blow up when using the blue training rounds, it was even a large gasoline type fire, when they hit the truck.
Did you notice how the model airplane even blew up when it crashed even though it wasn't hit, (model airplanes don't blow up like a hand grenade when they crash).
He should let people know that the target is rigged with pyro. Non-gun or anti-gun people are instantly going to be against guns due to seeing a building blown up from a few rifle rounds, or practice grenades.
Below I show link, that shows the color codes for MK-19 grenades.
Mk19 Grenade Machine Gun