There are various environmental and hazardous effects associated with current ammunition, the most deleterious being their heavy metal content. Hazardous heavy metals are present in two major areas of conventional small arms cartridges including the bullet core and the chemical compositions contained within the primer. Other areas of concern for volatile organic compounds (VOCs) and ozone depleting chemicals (ODCs) are the sealants, paints, and waterproofing compounds as well as the packaging material.
The objective of this program was to obtain technical solutions for producing non-toxic small caliber ammunition, which would meet U.S. and North Atlantic Treaty Organization performance standards for small caliber ammunition (5.56 mm, 7.62 mm, 9 mm, and .50 caliber). The effort focused on eliminating toxic components in the materials and manufacturing processes for the projectile core and primer.
For the projectile core, environmental studies of candidate projectile core materials were conducted to determine their viability as a non-toxic projectile and optimize methods for recovery with minimum release to the environment. The battery of environmental tests included leaching, corrosion, and biological uptake. These tests provided guidance for optimizing the environmental stability, recovery, and recycle ability of the next generation of projectile materials. For the cartridge primer, a new class of non-toxic energetic materials called Metastable Interstitial Composites (MIC) was evaluated as a replacement for current primer materials that contain lead styphnate, barium nitrate, and antimony sulfide. A MIC material is an engineered energetic consisting of two or more chemical species that are exothermically reactive.
Environmentally friendly, tungsten-based projectile core materials were successfully developed and will replace lead-antimony projectile core materials for the 5.56 mm, M855 ammunition. This success has resulted in plans to expand the technology to other small calibers such as 7.62 mm and 9 mm. The tungsten toxicology and chemical stability/leaching studies were completed for use as an essential information resource to eliminate heavy metals from other ammunition items.
To replace lead-styphnate-based primers, which contain barium and antimony, the investigation of MIC energetics has resulted in successful demonstration of an equal-to-baseline-velocity MIC material that meets operational extreme cold temperature (-65° F) requirements, which is a key parameter that has eluded non-toxic primer research throughout the 1990s. The fabrication of MIC constituents has been quantified and successfully demonstrated through the development of characterization methods. It is hoped that, as the MIC process is scaled up, manufacturing and yield will improve.
This project was completed in FY 2000 and has since transitioned to the Environmental Security Technology Certification Program as the project entitled Production Ramp-Up Demonstration of Ultra-Fine Aluminum to Support the Lead-Free MIC Percussion Primer.
The need for costly range cleanups will be eliminated without sacrificing the proficiency, performance, and readiness of Armed Forces personnel. Specifically, it is anticipated that the approximately $2.5 million required for waste removal at each outdoor firing range as well as the $100 thousand annual costs for lead contamination monitoring will be eliminated.