Most standard small-arms ammunition today still relies on lead as its primary component. Although the projectile may appear encased in a copper alloy, this “full metal jacket” typically surrounds a core made of lead or a lead alloy. This design is common for cartridges used in target practice, self-defense, and hunting. The continued use of lead in projectiles creates a significant, largely unregulated source of this toxic metal released into the environment, despite growing awareness of the health and environmental risks it poses.
Why Lead is Used in Ammunition Construction
Lead possesses a unique combination of physical characteristics that made it the material of choice for projectiles since the advent of firearms. Its high density is a major factor, allowing a bullet to retain greater mass in a smaller volume, which is essential for superior ballistic performance. A denser projectile maintains its velocity over longer distances, resulting in better accuracy and energy transfer upon impact.
The low melting point of lead, approximately 621°F (327°C), historically made it easy and inexpensive to cast into early bullets without specialized equipment. Lead is also an abundant commodity metal, making it far more cost-effective than denser alternatives like tungsten. Its relative softness, or malleability, is an advantage because it allows the bullet to easily engage with the spiral grooves, or rifling, inside a firearm’s barrel. This engagement imparts the necessary spin for stabilization in flight.
Risks Associated with Lead Ammunition Exposure
The widespread use of lead ammunition creates pathways for human and wildlife exposure to this potent neurotoxin. At indoor firing ranges, the act of firing causes lead from the bullet’s base and the primer compound (often lead styphnate) to vaporize and fragment into fine dust. This airborne lead poses an inhalation risk to shooters and range employees, leading to elevated blood lead levels. Lead particles can also settle on skin, clothing, and surfaces, leading to ingestion if proper decontamination is not followed.
For wildlife, the primary danger is secondary poisoning from ingesting spent lead fragments left in the field. When a lead-core bullet strikes an animal, it fragments into hundreds of tiny pieces that spread throughout the carcass or the remaining gut pile. Scavenging birds, such as California Condors and bald eagles, consume these contaminated remains and suffer from lead poisoning. Studies have documented lead exposure in over 130 wildlife species, including waterfowl that mistake spent lead shot for grit, causing neurological damage and mortality.
Non-Lead Ammunition Alternatives and Adoption
The movement away from lead has driven the development and adoption of high-performance alternatives, primarily based on other metals. Monolithic copper bullets are a leading substitute for rifle and handgun ammunition, offering excellent weight retention and deep penetration due to their non-fragmenting nature. For shotgun applications, steel shot is the most common and cost-effective alternative, though its lower density requires adjustments in shot size for comparable performance. Bismuth, which is softer and has a density closer to lead, is also available, particularly for use in older firearms.
Adoption of these alternatives has been driven by increasing regulation and conservation concern. Numerous jurisdictions, including the entire state of California, have implemented bans or restrictions on lead ammunition for hunting purposes. This shift is accelerating as non-lead options are now widely available and offer performance that meets or exceeds that of traditional lead ammunition.