Great idea, +1.

bullet could be like stone and destroy breakable metal but without pressure or heat.

slow down we already suggested bullet annd i think it was AntB and i were discussing how to make it without movable solids it will be like photons but in the shape of a bullet

ive been wantin something like this. +1

i have already suggested bullet element.
https://powdertoy.co.uk/Discussions/Thread/View.html?Thread=3086

BOMB could be counted as a standard projectile.