  Due to concerns about environmental and industrial hazards of lead, a number
of military, law enforcement, and wildlife management agencies are giving
careful consideration to lead-free ammunition. The goal of lead-free bullets is
to gain the advantages of reduced lead use in the environment while maintaining
equal or better terminal performance. Accepting reduced terminal performance
would foolishly risk the lives of military and law enforcement personnel. This
paper uses the established technique of studying bullet impacts in ballistic
gelatin to characterize the terminal performance of eight commercial off-the-
shelf lead-free handgun bullets for comparison with earlier analysis of
jacketed lead bullets. Peak retarding force and energy deposit in calibrated
ballistic gelatin are quantified using high speed video. The temporary stretch
cavities and permanent wound cavities are also characterized. Two factors tend
to reduce the terminal performance of these lead-free projectiles compared to
similar jacketed lead designs. First, solid copper construction increase barrel
friction, which reduces muzzle velocity and energy, and thus reduces the
ability of the bullet to exert damaging forces in tissue simulant. Second, the
lower density of copper requires a longer bullet for a given mass and caliber,
which reduces remaining powder volume in the brass cartridge case, which also
tends to reduce muzzle velocity and energy. The results of the present study
are consistent with earlier analysis showing that expansion is necessary to
maximize the potential for rapid incapacitation of enemy combatants. In spite
of some new non-expanding nose designs that moderately increase forces between
bullet and tissue, the largest retarding forces and highest incapacitation
potential requires expanding bullets which maximize frontal area.
