Traditional lead-core bullets can lead to environmental problems as lead accumulates in the soil at outdoor firing ranges. The contamination associated with lead left on ranges has the potential to pollute groundwater, which in turn can result in range closures. Furthermore, traditional projectiles leave a small amount of vaporized lead in the air at indoor firing ranges, exposing personnel to low levels of airborne lead. Tungsten has been identified as an alternative material to lead in bullet cores. In contrast to lead, tungsten is inert and will not cause ground contamination. Two composite materials with the same density as lead have been developed and are candidates for use in bullet cores—tungsten-nylon and tungsten-tin. Optimum parameters have been achieved in the M855 ball program. This demonstration investigated the extensibility of the technology to other rounds. Based on the results, an optimization program may be necessary to streamline the loading process or to correct poor performance in the 7.62mm rounds.
The objective of this demonstration was to compare the performance of cores made of the two tungsten alloys to traditional lead cores in M855, M856, M80, and M62 rounds. The rounds were tested in the M16A2 rifle, M249 machine gun, and M4 carbine weapons systems for 5.56mm rounds and the M240 machine gun for 7.62mm rounds. The testing took place in a controlled indoor range environment and encompassed some tests outlined in the small caliber ammunition test procedures (SCATP) guidance for 5.56mm and 7.62mm cartridges.
The M856 5.56mm tracer was dropped from the test plan during manufacturing due to safety concerns involving the loading of the tracer mix. Although the M856 was not mass produced, 100 rounds that had been made were test fired. Unofficial results of this impromptu test demonstrated that the accuracy of the lead-free tracer was sufficient to meet the accuracy requirements of the leaded ammunition. The M80 and M62 ball and tracer rounds were manufactured and tested at the Naval Surface Warfare Center in Crane, Indiana, as part of the independent (peer) review. Testing revealed that the 7.62mm ball and tracer lead-free (tungsten-nylon) rounds, while not fully optimized, both met required accuracy standards. The control (leaded) 7.62mm ball rounds had a higher accuracy (4.0 inches versus 7.1 inches) than the lead-free ball, but the leaded tracer had a lower accuracy (7.6 inches versus 5.4 inches) than the lead-free tracers.
The program is intended to make the material change completely transparent to end users (soldiers). Ammunition will be tracked by the military services through national stock numbers (NSN) and Department of Defense Identification Code (DoDIC) numbers. Labeling and marking of the packaging containers identifying “lead-free projectiles,” will be placed on wire bound boxes, metal cans, and fiberboard packing containers. The demonstration encompassed two main areas—the First Article test/standard lot testing for the corresponding lead-free ammunition and an ammunition-based qualification test. An Engineering Change Proposal has been submitted to the Configuration Control Board (CCB), which has the final determination as to whether the ammunition meets all the requirements and standards of the Technical Data Package for procurement. The engineering representative for the CCB has circulated the test plan for approval. Once approved for production and distribution, the ammunition will replace the M855, M856, M80, and M62 rounds.
Affected weapons systems include:
- M16A2 Rifle (series)
- M249 Squad Automatic Weapon
- M4 Carbine
- M240 G series Machine Gun
- M60 series Machine Gun
- M14 series