Action (firearms)
In firearms terminology, an action is the functional mechanism of a breechloading firearm that handles the ammunition cartridges, or the method by which that mechanism works. Actions are technically not present on muzzleloaders, as all those are single-shot firearms with a closed off breech with the powder and projectile manually loaded from the muzzle. Instead, the muzzleloader ignition mechanism is referred to as the lock.
Actions can be categorized in several ways, including single action versus double action, break action versus lever-action, pump-action, bolt-action, among many other types. The term action can also include short, long, and magnum if it is in reference to the length of the rifle's receiver and the length of the bolt. The short action rifle usually can accommodate a cartridge length of or smaller. The long action rifle can accommodate a cartridge of, and the magnum action rifle can accommodate cartridges of.
Single-shot actions
Single-shot actions operate only to ignite a cartridge that is separately set up for firing, and are incapable of moving the cartridge, itself. As the name implies, all single-shot firearms can only hold one round of ammunition and need to be manually reloaded after every firing. Historically, these are the earliest cartridge firearm actions invented.Breechblock
Dropping block
The dropping block are actions wherein the breechblock lowers or "drops" into the receiver to open the breech, usually actuated by an underlever. There are two principal types of dropping block: the tilting block and the falling block.Pivoting block
In a tilting block or pivoting block action, the breechblock is hinged on a pin mounted at the rear. When the lever is operated, the block tilts down and forward, exposing the chamber. The best-known pivoting block designs are the Peabody, the Peabody–Martini, and Ballard actions.The original Peabody rifles, manufactured by the Providence Tool Company, used a manually cocked side-hammer. Swiss gunsmith Friedrich Martini developed a pivoting block action by modifying the Peabody, which incorporated a hammerless striker that was cocked by the operating lever with the same single efficient motion that also pivoted the block. The 1871 Martini–Henry which replaced the "trapdoor" Snider–Enfield was the standard British Army rifle of the later Victorian era, and the Martini is also a popular action for civilian rifles.
Charles H. Ballard's self-cocking tilting-block action was produced by the Marlin Firearms Company from 1875 and earned a superlative reputation among long-range "Creedmoor" target shooters. Surviving Marlin Ballards are today highly prized by collectors, especially those mounted in the elaborate Swiss-style Schützen stocks of the day.
Falling block
In a falling block or sliding block action, a solid metal breechblock "slides" vertically in grooves cut into the breech of the firearm and actuated by a lever. Examples of firearms using the falling-block action are the Sharps rifle and Ruger No. 1.Rolling block
In a rolling block action, the breechblock takes the form of a part-cylinder, with a pivot pin through its axis. The operator rotates or "rolls" the block to open and close the breech; it is a simple, rugged, and reliable design. Rolling blocks are most often associated with firearms made by Remington in the late 19th century; in the Remington action the hammer serves to lock the breech closed at the moment of firing, and the block in turn prevents the hammer from falling with the breech open.Hinged block
The hinged block used in the earliest metallic-cartridge breechloaders designed for general military issue began as conversions of muzzle-loading rifle-muskets. The upper rear portion of the barrel was filed or milled away and replaced by a hinged breechblock, which opened upward to permit loading. An internal angled firing pin allowed the re-use of the rifle's existing side-hammer. The Allin action made by Springfield Arsenal in the US hinged forward; the Snider–Enfield used by the British opened to the side. Whereas the British quickly replaced the Snider with a dropping-block Peabody-style Martini action, the US Army felt the trapdoor action to be adequate and followed its muzzleloader conversions with the new-production Springfield Model 1873, which was the principal longarm used as a weapon in the Indian Wars and was still in service with some units in the Spanish–American War.Break-action
A break action is a type of firearm where the barrel are hinged and can be "broken open" to expose the breech. Multi-barrel break action firearms are usually subdivided into over-and-under or side-by-side configurations for two barrel configurations or "combination gun" when mixed rifle and shotgun barrels are used.Bolt-action
Although bolt-action guns are usually associated with fixed or detachable box magazines, some are single-shot. In fact, the first general-issue military breechloader was a single-shot bolt action: the paper-cartridge Prussian needle gun of 1841. France countered in 1866 with its superior Chassepot rifle, also a paper-cartridge bolt action. The first metallic-cartridge bolt actions in general military service were the Berdan Type II introduced by Russia in 1870, the Mauser Model 1871, and a modified Chassepot, the Gras rifle of 1874; all these were single-shots.Today, most top-level smallbore match rifles are single-shot bolt action rifles.
Single-shot bolt actions in.22 caliber were also widely manufactured as inexpensive "boys' guns" in the earlier 20th century; and there have been a few single-shot bolt-action shotguns, usually in.410 bore.
Eccentric screw action
The eccentric screw action first seen on the M1867 Werndl–Holub and later on the Magnum Research Lone Eagle pistol, the breech closure is a rotating drum with the same axis, but offset from the bore. When locked, a firing pin aligns with the primer, the breech is otherwise solid. When rotated open, a slot in the drum is exposed for extraction and feeding of a new round. Though first used on the Werndl-Holub, this action is commonly known as a cannon breech due to its association with the French 75mm Model of 1897 cannon. The French M1897 was, itself, based on William Hubbell's.Other actions
- The Ferguson rifle: British Major Patrick Ferguson designed his rifle, considered to be the first military breechloader in the 1770s. A plug-shaped breechblock was screw-threaded so that rotating the handle underneath would lower and raise it for loading with ball and loose powder; the flintlock action still required conventional priming.
- The Hall rifle: First U.S. cavalry breechloader, originally made in flint but later made-in and converted to percussion in 1830s–1840s. The breech section tilts up to accept a paper cartridge. Excellent machine-made construction, but still tended to leak gas at the breech.
- The Kammerlader: A crank-operated Norwegian firearm produced around the time of the Prussian Needle-gun. Originally used a paper cartridge. Later, many were converted to rimfire; this was the first Norwegian breechloader.
- The Tarpley carbine: This is categorized into falling block action, but the breech block is hinged, unlike the others.
- The Morse Carbine: This mostly brass action is somewhat like the Hall rifle, except it was designed to take a special centerfire cartridge. Very few of these were actually made; all were constructed in the late 1850s.
- The Joslyn rifle:
- Rising Breech Carbine:
Repeating actions
Manual operation
Revolver
A revolver is a multi-chamber firearm that houses cartridges in a rotary cylinder which indexes each round into alignment with the bore prior to each shot. Revolvers are most often handguns; however, examples of revolving rifles, shotguns, and cannons have been made. The cylinder is most often rotated via linkage to a manually manipulated external hammer, although some revolvers are "double-action" and can use the manual pull of the trigger to drive both the cylinder rotation and hammer cocking. Some examples of firearms using the revolver principle are the Smith & Wesson Model 3 and Colt Model 1889.Bolt action
In bolt-action firearms, the opening and closing of the breech is operated by direct manual manipulation of the bolt via a protruding bolt handle.Rotating bolt action
Most bolt-actions utilize a rotating bolt design, where the bolt handle must be rotated upwards for unlocking before the bolt can be pulled back to opening the breech and eject any spent cartridge, and must be rotated back down for locking after the bolt closes the breech. The three predominant rotating bolt-action systems are the Mauser, Lee–Enfield, and Mosin–Nagant systems, with the Mauser system emerging into the mainstream as the most widely used rotating bolt-action design.Straight-pull action
There are also straight pull bolt-action systems that use complex bolt head designs to facilitate locking instead of needing to rotate the bolt handle every time.In the Mauser-style turn-bolt action, the bolt handle must be rotated upward, pull rearward, pushed forward, and finally rotated back downward into lock. In a straight pull bolt-action, the bolt can be cycled without rotating, hence reducing the required range of motion by the shooter from four movements to two, with the goal of increasing the rate of fire. The Ross and Schmidt–Rubin rifles load via stripper clips, albeit of an unusual paperboard and steel design in the Schmidt–Rubin rifle, while the Mannlicher uses en-bloc clips. The Schmidt–Rubin series, which culminated in the K31, are also known for being among the most accurate military service rifles ever made. Yet another variant of the straight pull bolt-action, of which the M1895 Lee Navy is an example, is a camming action in which pulling the bolt handle causes the bolt to rock, freeing a stud from the receiver and unlocking the bolt.
In 1993, the German firearms
company Blaser, introduced the Blaser R93, a new straight pull bolt-action rifle where locking is achieved by a series of concentric "claws" that protrude/retract from the bolthead, a design that is referred to as Radialbundverschluss. As of 2017 the Rifle Shooter magazine listed its successor Blaser R8 as one of the three most popular straight pull bolt-action together with Merkel Helix and Browning Maral. Some other notable modern straight pull bolt-action rifles are made by Chapuis, Heym, Lynx, Rößler, Strasser, and Steel Action.
In the sport of biathlon, because shooting speed is an important performance factor and semi-automatic guns are illegal for race use, straight pull bolt-actions are quite common, and are used almost exclusively on the Biathlon World Cup. The first company to make straight pull bolt-actions for.22 caliber was J. G. Anschütz; the action is specifically the straight-pull ball bearing-lock action, which features spring-loaded ball bearings on the side of the bolt which lock into a groove inside the bolt's housing. With the new design came a new dry-fire method; instead of the bolt being turned up slightly, the action is locked back to catch the firing pin.