Nammo MAC LLC has secured a $95 million contract from the U.S. Marine Corps Systems Command for the production of lightweight .50 caliber polymer-cased ammunition, the Department of Defense announced Tuesday.
The contract includes a five-year ordering period, running from June 10, 2025, through June 9, 2030. The ammunition will be produced at Nammo MAC’s facility in Bay St. Louis, Mississippi. The initial delivery order, valued at $2,026,000, will be funded by Fiscal Year 2025 Navy and Marine Corps procurement accounts.
According to a statement from Nammo, the polymer-cased .50 caliber round is fully compliant with MIL-DTL-10190F specifications and is currently in service with the U.S. Marine Corps, U.S. Special Operations Command (SOCOM), and allied forces.
Nammo says the ammunition delivers up to a 30 percent weight reduction compared to traditional brass-cased rounds, depending on configuration. That reduction directly supports force mobility and logistics efficiency, particularly in dismounted and air-mobile operations.
The .50 caliber polymer ammunition is compatible with a wide range of legacy weapons, including the M2HB, M3 variants, XM-806, GAU-19A/B, GAU-21, and Barrett M107 and M82 series rifles. The company describes the cartridge as a direct, drop-in replacement for brass-cased ammunition, requiring no weapon modifications.
Beyond weight reduction, the polymer case contributes to improved ballistic consistency. According to Nammo, the design reduces standard deviations in velocity and chamber pressure, helping improve accuracy and reliability. It also acts as a thermal insulator, limiting heat transfer to the chamber and reducing the risk of cook-offs during sustained fire.
In a statement, the Marine Corps said the contract was awarded under U.S. Code 3204(a)(7), citing public interest as the justification for a sole-source award. The decision reflects the system’s current fielding status and the absence of comparable alternatives offering the same performance and logistical benefits.
Nammo’s polymer ammunition technology has undergone multiple evaluations and has already been integrated into operational units. Its use is expanding within U.S. and international forces seeking to streamline logistics chains and improve system performance under sustained combat conditions.
Work under the new contract will continue at Nammo MAC’s production facility, which serves as a center for the company’s polymer casing development and manufacturing.