Bolt action is a type of firearm action in which the weapon's bolt is operated manually by the opening and closing of the breech (barrel) with a small handle, most commonly placed on the right-hand side of the weapon (for right-handed users). As the handle is operated, the bolt is unlocked, the breech is opened, the spent cartridge case is withdrawn and ejected, the firing pin is cocked (this occurs either on the opening or closing of the bolt, depending on design), and finally a new round/cartridge (if available) is placed into the breech and the bolt closed. Bolt-action firearms are most often rifles, but there are some bolt-action shotguns and a few handguns as well. Examples of this system date as far back as the early 19th century, notably in the Dreyse needle gun. From the late 19th century, all the way through both World Wars, the bolt-action rifle was the standard infantry firearm for most of the world's militaries.
In military and law enforcement use, the bolt action has been mostly replaced by semi-automatic and selective-fire firearms, though the bolt action remains the dominant design in dedicated marksman rifles. Bolt-action firearms are still very popular for hunting and target shooting. Compared to most other manually operated firearm actions, it offers an excellent balance of strength (allowing powerful cartridge chamberings), ruggedness, reliability, and potential accuracy, all with light weight and much lower cost than self-loading firearms, and can also be disassembled and re-assembled much faster due to fewer moving parts. The major disadvantage is a slightly lower practical rate of fire than other manual repeating firearms, such as lever-action and pump-action firearms, and a far lower practical rate of fire than semi-automatic weapons, but this is not a very important factor in many types of hunting, target shooting, and other precision-based shooting uses.