Lead ammunition is superior to alternative ammunition in terminal performance. Due to the density and malleability of lead, it penetrates and expands more reliably upon impact at a wider range of velocities, thereby delivering quicker more humane kills. Thus, lead ammunition has a higher kill rate in comparison to most alternative ammunition.
Studies demonstrate a good frequency of circular exit wounds in wildlife shot with jacketed lead ammunition. This indicates that significant portions of the projectile are not disintegrating in a manner that deposits significant amounts of lead fragments in or near the wound channel.
Steel shot is inferior in terminal performance because it is harder, less dense, and less malleable than lead ammunition. Because the density and deformation of ammunition can affect terminal performance, steel ammunition can cause crippling of game where lead ammunition would have successfully delivered a kill. Steel ammunition also presents major concerns for hunters associated with bullet ricochet when striking a hard object.
Ironically, while copper ammunition has been promoted as a “non-toxic” alternative to lead, and is commonly used in small amounts in lead ammunition, copper ammunition itself has been alleged to be toxic to wildlife in and around an aquatic environment.
The U.S. Fish and Wildlife Service dismissed zinc as a non-lead alternative because it was found to be highly toxic when administered to waterfowl.
Bismuth demonstrates superior ballistic performance to other non-lead alternatives such as steel. However, recent studies have questioned whether bismuth is an appropriate ammunition alternative. Excessive exposure to bismuth has been alleged to be linked to blood, liver, and neural problems.
Tungsten ammunition has been promoted as a superior “green” alternative metal to lead. However, several studies have shown tungsten to be a toxic carcinogen. One study, sponsored by the U.S. EPA, found that tungsten may be associated with elevated cancer rates in Fallon, Nevada (Sheppard, et al. 2007). Another study on tungsten found that it is highly soluble making it bioavailable to wildlife. This study found that after ingestion, tungsten accumulates in the spleen causing immune system disorders. Because of these studies, the U.S. Army discontinued its use of tungsten ammunition.