Action (firearms)

A view of the break-action of a typical double-barreled shotgun, with the action open and the extractor visible. The opening lever and the safety catch can also be clearly seen.

In firearms terminology, an action is the mechanism of a breech-loading weapon that handles the ammunition (loads, locks, fires, extracts and ejects) or the method by which that mechanism works.[1] Actions are technically not present on muzzleloaders, as all are single-shot weapons with a closed off breech. Instead, the ignition mechanism is referred to (Matchlock, Flintlock, etc.)

Actions can be categorized in several ways, including single action versus double action, break action versus bolt action, and others. 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 2.8 in (71 mm) or smaller. The long action rifle can accommodate a cartridge of 3.34 in (85 mm), and the magnum action rifle can accommodate cartridges of 3.6 in (91 mm), or longer in length.[2]

Single shot actions

Firearm actions

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.

Tilting 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, that incorporated a hammerless striker which 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 was 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
Ruger No. 1 single-shot falling-block rifle with action open

A falling block action (also known as a sliding block action) is a single-shot firearm action in which a solid metal breechblock slides vertically in grooves cut into the breech of the weapon 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 later 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 was 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 of 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(s) 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, 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 actions.

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.

Rotating-drum action

The rotating-drum action first seen on the M1867 Werndl–Holub and later on the U.S. Patent 149,478.

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: