Most commonly, cartridge cases were brass, and shell bodies were steel. Cartridge cases (which were left behind when the shell was fired) were returned for recycling when possible.

Armour-piercing explosive shells had thick steel bodies to survive penetration into the target (and then explode in target). Shells intended to explode on contact (e.g., high explosive shells, gas shells) or before contact (e.g., shrapnel shells) had thin steel shell bodies. Shrapnel shells and fragmentation shells also contained lead balls, and sometimes cast iron waffles, which were spread by the bursting charge - in this case, the balls and fragments were intended to cause the main damage (to enemy soldiers). The steel shell bodies of high explosive shells also produced lethal fragments, but this was secondary to their main intended explosive effect.

The basic pattern of brass cartridge cases and steel shell bodies continued into World War Two, although there was greater use of steel cartridge cases than before. More modern artillery cartridge cases use a wider range of materials, including aluminium and plastic in addition to brass and steel.

For an overview of WW1 artillery ammunition, including many photos, see http://www.passioncompassion1418.com/decouvertes/english_fusees_munitions.html