- For ammunition used by shotguns, see shotgun shell.
Shells are projectiles that are fired out of a firearm or larger weapon (such as a mortar) in a manner similar to a bullet; unlike a bullet, shells usually carry an explosive charge in them. They are generally found in artillery.
A shell is also (incorrectly) referred to as the discarded portion of a cartridge after being fired; in this case, the "shell" is the casing.