US Army unveils SixPAC, new lightweight small-caliber ammunition packaging system

Credit: Eric Kowal, Army

The US Army has introduced SixPAC, a new packaging system for small-calibre ammunition made from lightweight polymer and steel components. This represents the first major update to small-calibre ammunition packaging since the Second World War, according to an Army release dated 26 August 2026.

Design and Composition

Developed by the US Army Combat Capabilities Development Command Armaments Center, the SixPAC system consists of two polymer ammunition containers housed within a steel outer case. Initially designed for 6.8 mm cartridges, the system is intended to be introduced in phases across multiple existing small-calibre ammunition production lines.

Key Advantages

The SixPAC system eliminates the need for wooden cases, which previously required manual assembly and were vulnerable to mould and degradation in challenging climates.

Jason Runell, the project’s technical lead, stated that the aim was to address the shortcomings of wood packaging and improve efficiency and portability for modern military demands.

Edward Lucas, a mechanical engineer and polymer designer at the centre, commented:

"It’s a developing field, and polymers are unique — you can modify them, include additives that improve impact performance, stiffness or dimensional stability. You can add more ingredients to the cauldron and your potion will come out different, trading some characteristics for others."

Weight Reduction and Mobility

According to the DoW, multiple designs for the inner tactical polymer containers are being considered, with the goal of weighing approximately half as much as existing steel versions. This reduction in weight is intended to:

• Lessen the physical burden on soldiers
• Support mobility in the field
• Benefit weight-restricted platforms such as watercraft and aircraft, where overall load directly impacts operational performance and manoeuvrability

Manufacturing and Supply Chain

Manufacturing the polymer containers by injection moulding could broaden the supply base, with more than 800 potential suppliers identified in the US. This method allows for a streamlined production process, as parts can be made using interchangeable moulds on existing equipment, reducing the need for dedicated manufacturing facilities and specialised tooling.

Testing and Future Development

The SixPAC system has been tested by soldiers throughout 2024 and into 2025, with user feedback informing ongoing design refinements. While the inner polymer pack remains under evaluation, the initiative is expected to continue with investment in multiple container designs and further collaboration with industry partners.