Bullets kill you because of the speed it comes out of the gun. A bullet itself is not deadly, unless it is made out of a poisonous metal. In which case, anything made from that metal would kill you, not just the bullet.
So, a bullet isn't designed to kill you unless it's shot from a gun, a bullet by itself is harmless to you.
Swallowing a bullet made from lead etc would have the same effect on you that swallowing something different made from lead would have.