Ammunition packaging has multiple purposes, primarily to protect and store, then to deliver the ammo in shooting condition when and where needed. Since the route from manufacturing plant to the front line can be tortured and hazardous, with long periods of storage included, most small arms ammunition is packed in watertight metal boxes of convenient size for humping to the soldier/consumer. They can be stacked and palletized for bulk shipment and storage, then broken down to individual boxes for a gun crew. These ammo cans are ubiquitous on the battlefield, especially in the vicinity of machine guns. As surplus, they have found their way by the millions into many a garage or basement as tool boxes, tackle boxes, or generally useful container.
Empty and full M2A1 .50 caliber Ammunition Cans with lids removed, at the firing range, Fort Dix, NJ, 30 Jan 2009.
Although often called "ammo cans", military nomenclature refers to "Box, Metal, M2A1" not a ".50 cal. ammo can." An ammunition can, to the military, is usually a factory-sealed metal container that is opened at the point of use, then discarded like a coffee can. The ammo box, in contrast, has a clamp-on lid that opens and closes for use multiple times. Used boxes are recovered, where practical, and sent back to be refilled.
The boxes sized for .30 cal. and .50 cal. ammunition are the most common, but there are actually a large number of sizes and shapes of ammo cans to accommodate the vast variety of military cartridges and munitions. Some boxes are special purpose containers made for one item exclusively, such as an artillery shell. Others are more general purpose and can be packed with inner cartons, bandoleers, linked belts, dividers, or loose cartridges of many types or calibers. They are sized based on weight of the filled box (to make it convenient for hand carry) or in a size the fits the characteristics of the weapon and ammunition.
Although there is a lot of variation, ammo cans are often marked by embossing or stencil to indicate the orientation of the ammo contents, the box nomenclature, and the manufacturer. They are usually stenciled on the outside to indicate contents and manufacturing lot numbers. As the box designs have evolved, so have the markings.
When the ammo box contains linked belts for an infantry machine gun, the box can be used with an accessory fitted tray on the gun that holds the ammunition box in proper alignment for feeding. The arrangement is flexible, however, so the gun can be hand-fed by a loader when necessary, drawing the belt from an ammo box on the ground. Combat photos show ammo boxes in all types of usage, according to the field manual as well as expedients that work for the moment.
Aircraft machine guns, naval guns and specialized mounts (eg, the Quad 50) do not use the standard ammunition boxes. These machine guns have a high rate of fire and are supplied through specialized ammunition containers designed for that particular weapon.
This is a list of the most common types of ammo boxes, linked to the Olive-Drab.com pages with more information and photos specific to each type:
Many of the ammunition containers developed after World War II were then in use for decades. For training purposes the U.S. military has been experimenting with fiberboard boxes for 5.56mm ammo to save on the cost of delivering ammo cans, bandoleers and other disposable packaging. Other improvements in the works involve protected pallets so ammo cans do not have to be enclosed in wirebound wood crates. Mission packaging is not changed, bandoleers and ammo cans will still be used.
There are many fine websites that have additional information on this
topic, too many to list here and too many to keep up with as they come and go.
Use this Google web search form to get an up to date report of what's out there.
For good results, try entering this: ammo can box. Then click the Search button.