An ammunition box or cartouche box is a container designed for safe transport and storage of ammunition. Known ammunition boxes are typically made of steel plates and labelled with caliber, quantity, and manufacturing date or lot number. A rubber gasket is commonly found in the hinged lid to protect the ammunition from moisture damage. The resealing ammunition box is largely a NATO tradition.
For military ammunition, there are strict guidelines on how ammunition is to be handled, and there are various requirements for ammunition boxes, since they have to be capable of withstanding hostile environments, and must be strong enough to protect the ammunition from exploding, should the ammunition box be dropped to a hard surface.
The North Atlantic Treaty Organisation (NATO) has specified ammunition standards including specific requirements for ammunition boxes. The ammunition boxes have to have a specific size, both inside and outside, so that the container is easily recognizable suitable for a specific type of ammunition, and have a specified outer shape and sizes so that the ammunition boxes can be easily be stacked on pallets for bulk transportation. An example of such standardized ammunition boxes is the M19A1 ammunition box for 7.62×51 mm NATO cartridges. Other models of ammunition boxes are used for other types of standard NATO ammunition, where the size of the container reflects the size of the ammunition. In addition to the standardized size and design of the ammunition containers, the containers used for NATO ammunition are required to withstand the extreme environments, to which the ammunition containers are supposed to be in, such as extreme cold and extreme heat and must be able to preserve the ammunition in storage for a minimum of 20 years. In all these conditions the ammunition container must be in working order, so that the ammunition may be transported and accessed without any hindrance. The above requirements may be seen as the normal use requirements for a NATO ammunition container, where there are further requirements for the container that covers extraordinary situations, such as if the container is damaged. The container must be capable of withstanding shocks or impacts within a predetermined range, in order to ensure that the container maintains its mechanical structure for holding and transporting the ammunition in case the container is damaged. The predefined range of tolerance is for example that the container must be able to hold the ammunition, be carried by a handle, and be openable when a container filled with ammunition has been dropped from at height of 12 meters to a hard surface, such as concrete, in a cold environment of −47° C.
Such reliability of NATO ammunition containers has been achieved by constructing the ammunition boxes from steel plating since the mechanical strength of the steel is not significantly affected by change in temperature, within a predetermined range from about −47° C. to 70° C. A steel plating box is also highly resistant to shocks or impacts, meaning that the structural integrity of the ammunition box is maintained even if the container is dropped from a significant height. The steel plating may bulge and be indented after the fall, but the steel construction is stable enough to allow the container to maintain its substantial shape, without disintegrating. Furthermore, the steel ammunition box is of such a mechanical strength that it is capable of being stacked in large bulks on pallets for bulk transportation, where the lowest placed ammunition boxes the stack may bear the weight of approximately 20 fully loaded ammunition containers stacked thereon.
Although steel ammunition boxes have been used since the Second World War (1940s) and have served its purpose fully, steel ammunition boxes have a number of drawbacks. A conventional steel container that fulfils the NATO requirements uses relative thick steel plating, resulting in an ammunition box that has a relatively high weight compared to the weight of the ammunition. This is disadvantageous since ammunition is often transported in bulk to a distant location of deployment by air. Since weight is typically the main load capacity restriction of an airplane, reduced weight is of significant advantage.
Furthermore, even though the material cost of steel is currently relatively low, the assembly and construction of steel cases is relatively expensive, as the steel panels have to be formed into its shape and welded into its shape. This construction is time consuming, either for skilled metal workers or robots that are performing the construction and assembly operations.
Known ammunition boxes in plastic are both designed with ribs that are arranged at a right angle relative to the housing of the box, which is normal design procedure in the plastic industry to increase stiffness. This measure will have some minor resistance to impacts. However, if the impact is too hard, these ribs will not collapse but transfer the impact energy straight into the case where the ribs are attached and therefor cause the wall of the box to break at the connection line.
Thus, there is a need to provide an ammunition box that is lightweight, inexpensive in production and is capable of meeting the minimum standards that are required for use within the NATO alliance.