casing b 0028 fig6 a cutaway of the finished u201c safety bullet u201d show the shell casing b with the groove d pressed in the side of the shell casing as a v that would extend around the entire circumference of the shell casing b the propellant a is in the firing end of the u201c safety bullet u201d with the metal ram c up against it forward of the inboard end of the metal ram c is a space for the metal ram c to travel when the u201c safety bullet u201d is fired to allow it to be pushed to its resting place against the inboard end of the plastic expander e in doing so the tapered end has been pushed through the expander e and has forced the expander e up against the inside of the firearm the body of the expander e is of a smaller diameter than the inside of the shell casing b so that when the u201c safety bullet u201d is fired it will have room to expand without this space most of the effectiveness of the u201c safety bullet u201d would be lost 0029 fig7 cutaway of the u201c safety bullet u201d after firing showing that the propellant charge a is gone.