whoah whoah whoah..... "break instantly"?
If a 3.2 gram paintball traveling at 285 feet per second were to hit fiberglass armor and shatter it, that would equate to extensive tissue damage and some penetration on uncovered body parts.
thats absurd.
Again the average weight of a premium grade paintball (which are the heaviest) is around 3.2 grams. if its accelerated up to 285 fps and hits instantly (point blank) thats going to equate to roughly 0.277 Newtons, or 0.062 pounds of force.
Given that the paintball is about 96% liquid paint by weight, and the other 4% is a thin brittle shell made of the same material they make gelcap medicine out of, and also the fact that the armor has inelastic qualities associated with its structure, whereas a paintball is designed to shatter on contact with any surface having near-zero elasticity to it -- the force imparted to the armor from a paintball will have a negligible effect on it.
I've posted this video up in another thread before to attest the strength of a foam/fiberglass/epoxy composite compared to aluminum.
If it could stand up to such a big guy jumping on it repeatedly, it can stand up to some paintballs hitting with less than half a pound of force.