The US Army has revealed SixPAC, a new packaging made of lightweight polymer and steel components for small-calibre ammunition.
This marks the first major update to small-calibre ammunition packaging since the Second World War, the Army stated in a release on 26 August 2026.
The US Army Combat Capabilities Development Command Armaments Center’s SixPAC system consists of two polymer ammunition containers housed within a steel outer case.
Initially designed for 6.8 mm cartridges, the system is also intended to be introduced in phases across multiple existing small-calibre ammunition production lines.
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 said the project’s 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 said: “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.”
According to the DoW, multiple designs for the inner tactical polymer containers are being considered to weigh approximately half as much as existing steel versions.
This reduction in weight is intended to lessen the physical burden on soldiers and support their mobility in the field.
The lighter packaging is also intended to benefit weight-restricted platforms such as watercraft and aircraft, where overall load directly impacts operational performance and manoeuvrability.
In addition, 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.
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.
