In San Fierro the bullet is near the garage you fisrt purchase in San Fierro. From CJs garage go right, and then take your first left. Should go over the train tracks kind of round a bend and down a hill. When you reach the bottom of the hill take a right, there is an opening in the wall on the left hand side. There is a bullet (or GT40 i think it is in real life) and also a police star thing to reduce wanted level. It is there all day and respawns after you used it.
I have two in my garage with nitros
If you cant find it, from my relativly poor directions, ask and i shall try again.