In general, a small caliber firearm designed to be operated with one or both hands. Usually has a small capacity magazine and short barrel. Some design variants in use today include the revolver, semi-automatic, and break-action derringer. Most utilize iron sights, but some accept scope mounts. Popular calibers include the 9mm, .44 Magnum, .45 ACP, .38 Special, .357 Magnum, and .22 Long Rifle.