Break action

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

Break action is a type of firearm action in which the barrel or barrels are hinged much like a door and rotate perpendicularly to the bore axis to expose the breech and allow loading and unloading of cartridges. A separate operation may be required for the cocking of a hammer to fire the new round. There are many types of break-action firearms; break actions are universal in double-barrelled shotguns, double-barrelled rifles, combination guns, and are also common in single shot pistols (especially derringers), rifles, shotguns, and can also be found in flare guns, grenade launchers, air guns, and some older revolver designs. They are also known as hinge-action, break-open, break-barrel, break-top, or, on old revolvers, top-break actions.

Contents

Description

Break action

Close-up of an IOF 32 break-action revolver IOF-32-REV-4.JPG
Close-up of an IOF 32 break-action revolver

The first break-action revolver was patented in France and Britain at the end of December in 1858 by Devisme. [1] A substantial hinge pin joins the two parts of the rifle or shotgun; the stock with its firing mechanism and the fore-piece and barrel, which hold the round to be fired. In some cases the hinging pin may be easily removable, allowing the two portions of the weapon to be compactly and safely stored. In other cases the hinge will consist of a hook over a pin; releasing an auxiliary latch will allow sufficient travel to allow the hinge to be unhooked.

A latch is operated to release the two parts of the weapon, allowing the breech to be exposed. Rounds are inserted into the breech, loading as many barrels (rifle or shotgun) or chambers (revolver) as desired, and the mechanism is closed and latched. The hammer is then pulled back and latched. The weapon can now be fired by squeezing the trigger.

After firing the rounds, the break action is unlatched and the barrel and forearm are allowed to fall forward. This causes an extractor catch to remove the spent shells so that they fall to the ground, leaving the weapon ready for reloading.

Tip-up action

Smith & Wesson Model 1 Third Issue open Mod1open.jpg
Smith & Wesson Model 1 Third Issue open

The tip-up was the first revolver design for use with metallic cartridges in the Smith & Wesson Model 1, on which the barrel pivoted upwards, hinged on the forward end of the top strap. On S&W tip-up revolvers, the barrel release catch is located on both sides of the frame in front of the trigger.

Advantages

A break action is one of the most compact firearm actions. Since there are no parts to reciprocate, it is shorter than repeating designs, and generally more compact than other non-repeating firearms such as falling block and rolling block actions. This compactness results in reductions in weight and size compared to larger actions; this can also allow a longer barrel in a firearm of similar size.

Since the cartridge extractor or ejector is built into the barrel assembly in break action weapons, the breech face is simply a flat plate with a hole for the firing pin to protrude through. This makes break actions ideal for interchangeable barrel firearms, such as the popular Thompson/Center Arms Contender and Encore pistols. The simplicity of the break open design, especially with an external hammer, also reduces the cost of manufacture. There were a number of companies, such as H&R Firearms, that produced break action rifles at lower costs than comparable bolt-action rifles.

While most firearms are designed for right-handed shooters, break action guns operate identically when fired from either shoulder.

Another advantage of the break action is the ability to insert longer cartridges into the chamber. This allows cartridges of a length impractical in other designs; as well as easy use of caliber conversion sleeves. It is common to find conversion sleeves for double barrel shotguns, allowing the firing of smaller gauge shells as well as sub-bore pistol and rifle cartridges (and thus allowing the same gun to be used with, for example, 10 gauge through 28 gauge, as well as .410 bore shells). [2]

Disadvantages

The break action design is best suited for non-repeating firearms. To get multiple shots requires either multiple barrels or a revolver cylinder; while this is fairly simple for shotguns, with double-barreled shotguns being quite common and even four-barreled designs like the FAMARS Rombo are available, double rifles require very precise alignment of the barrels in order to achieve consistent accuracy. Modern double rifles are very expensive and designed for short-range use; the barrels are often regulated for ranges under 100 yards (91 m) for use against dangerous game.

Wear in the mechanism is focused upon the small contact area of the latch, and the breech is difficult to seal properly once the latch wears. In some firearms, such as Thompson/Center guns, the latch is a removable part that could be replaced when worn. Designs without a replaceable latch may be fixed by building up the worn part with a welder, then filing it back into shape.

Break-open actions are also not as inherently strong as other action types, rendering them capable of withstanding only relatively low pressures. The action is usually held closed by a single locking lug, usually below the barrel in a single barrelled gun or between the barrels of a double barreled gun. The single lug must carry all of the force of firing the cartridge. For shotguns, which operate at very low pressures, this is not an issue.

Some centerfire rifle cartridges, however, can generate pressures that may be too great for a single locking lug, if it is not stout enough. The Thompson/Center Contender, for example, was limited to .30-30 Winchester level cartridges. To fire more powerful cartridges requires a much larger locking lug, such as that which Thomson Center used on the larger Encore model. By comparison, while bolt-action shotguns may only use a single locking lug, almost all bolt-action rifles use multiple locking lugs around the perimeter of the bolt to provide an even distribution of the forces of firing, providing a much higher intrinsic strength. Since many break action rifles, such as the inexpensive H&R models, are built on large frames originally meant for shotguns, the action is very heavily built and capable of handling moderate to high pressures. Still, belted magnum cartridges such as .300 Winchester Magnum are generally only found in the highest-quality break action rifles.

Break open designs work best with rimmed cartridges, which can use a solid extractor. Rimless cartridges require a spring-loaded extractor, which can slide out of the way for cartridge insertion, and spring back to engage the recessed rim. While these spring-loaded extractors are found on even inexpensive models, they are not as strong as solid extractors, and increase the likelihood that failures to extract will occur.

Other long gun actions

See also

Related Research Articles

Revolver Firearm with a cylinder holding cartridges

A revolver is a repeating handgun that has at least one barrel and uses a revolving cylinder containing multiple chambers for firing. Before firing a round, cocking the hammer partially rotates the cylinder, indexing one of the cylinder chambers into alignment with the barrel, allowing the bullet to be fired through the bore. The hammer cocking can be achieved by either the user manually pulling the hammer back, via internal linkage relaying a rearward movement of the trigger, or both. By sequentially rotating through each chamber, the revolver allows the user to fire multiple times until having to reload the gun, unlike older single-shot firearms that had to be reloaded after each shot.

Single-shot

Single-shot firearms are firearms that hold only a single round of ammunition, and must be reloaded manually after every shot. The history of firearms began with single-shot designs, then multi-barreled designs appeared, and eventually many centuries passed before multi-shot repeater designs became commonplace.

Bolt action Type of firearm mechanism

Bolt action is a type of manual firearm action that is operated by directly manipulating the bolt via a bolt handle, which is most commonly placed on the right-hand side of the weapon.

Action (firearms) Functional mechanism of breech-loading

In firearms terminology, an action is the functional mechanism of a breech-loading 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.

A semi-automatic firearm, also called a self-loading or autoloading firearm, is a repeating firearm whose action mechanism automatically loads a following round of cartridge into the chamber (self-loading) and prepares it for subsequent firing, but requires the shooter to manually actuate the trigger in order to discharge each shot. Typically, this involves the weapon's action utilizing the excess energy released during the preceding shot to unlock and move the bolt, extracting and ejecting the spent cartridge case from the chamber, re-cocking the firing mechanism, and loading a new cartridge into the firing chamber, all without input from the user. To fire again, however, the user must actively release the trigger, allow it to "reset", before pulling the trigger again to fire off the next round. As a result, each trigger-pull only discharges a single round from a semi-automatic weapon, as opposed to a fully automatic weapon, which will shoot continuously as long as the ammunition is replete and the trigger is kept depressed.

Semi-automatic pistol Type of pistol

A semi-automatic pistol is a type of repeating single-chamber handgun (pistol) that automatically cycles its action to insert the subsequent cartridge into the chamber (self-loading), but requires manual actuation of the trigger to actually discharge the following shot. As a result, only one round of ammunition is fired each time the trigger is pulled, as the pistol's fire control group disconnects the trigger mechanism from the firing pin/striker until the trigger has been released and reset.

Breechloader Class of gun

A breechloader is a firearm in which the user loads the ammunition via the rear (breech) end of its barrel, as opposed to a muzzleloader, which loads ammunition via the front (muzzle).

A repeating rifle is a single-barreled rifle capable of repeated discharges between each ammunition reloads. This is typically achieved by having multiple cartridges stored in a magazine and then fed individually into the chamber by a reciprocating bolt, via either a manual or automatic action mechanism, while the act of chambering the round typically also recocks the hammer/striker for the following shot. In common usage, the term "repeating rifle" most often refers specifically to manual repeating rifles, as opposed to self-loading rifles, which use the recoil and/or blowback of the previous shot to cycle the action and load the next round, even though all self-loading firearms are technically a subcategory of repeating firearms.

Lever action Type of firearm action

Lever action is a type of action for repeating firearms that uses a manually operated cocking handle located around the trigger guard area that pivots forward to move the bolt via internal linkages, which will feed and extract cartridges into and out of the chamber, and cock the firing pin mechanism. This contrasts to other type of repeating actions such as the bolt-action, pump-action, semi-automatic, or automatic/selective-fire actions. A firearm using this operating mechanism is colloquially referred to as a levergun.

Breechblock

A breechblock is the part of the firearm action that closes the breech of a breech loading weapon before or at the moment of firing. It seals the breech and contains the pressure generated by the ignited propellant. Retracting the breechblock allows the chamber to be loaded with a cartridge.

Lock (firearm)

The lock of a firearm is the mechanism used to initiate firing. It is an historical term, in that it generally refers to such mechanisms used in muzzle-loading and early breech-loading firearms. Side-lock refers to the type of construction, in which the individual components of the mechanism are mounted either side of a single plate. The assembly is then mounted to the stock on the side of the firearm. In modern firearm designs, the mechanism to initiate firing is generally constructed within the frame or receiver of the firearm and is referred to as the firing or trigger mechanism.

Gas-operated reloading System of operation used to provide energy to operate autoloading firearms

Gas-operation is a system of operation used to provide energy to operate locked breech, autoloading firearms. In gas-operation, a portion of high-pressure gas from the cartridge being fired is used to power a mechanism to dispose of the spent case and insert a new cartridge into the chamber. Energy from the gas is harnessed through either a port in the barrel or a trap at the muzzle. This high-pressure gas impinges on a surface such as a piston head to provide motion for unlocking of the action, extraction of the spent case, ejection, cocking of the hammer or striker, chambering of a fresh cartridge, and locking of the action.

Rotating bolt Method of locking used in firearms

Rotating bolt is a method of locking the breech of a firearm closed for firing. Johann Nicolaus von Dreyse developed the first rotating bolt firearm, the "Dreyse needle gun", in 1836. Like the Mauser M 98 or M16, the Dreyse locked using the bolt handle rather than lugs on the bolt head. The first rotating bolt rifle with two lugs on the bolt head was the Lebel Model 1886 rifle. The concept has been implemented on most firearms chambered for high powered cartridges since the 20th century.

H&R Firearms Harrington and Richardson firearms manufacturer

H&R 1871, LLC is a manufacturer of firearms under the Harrington & Richardson and New England Firearms trademarks. H&R is a subsidiary of JJE Capital Holdings. H&R ceased production February 27, 2015.

Hammerless

A hammerless firearm is a firearm that lacks an exposed hammer or hammer spur. Although it may not literally lack a hammer, it lacks a hammer that the user can pull directly. One of the disadvantages of an exposed hammer spur is the tendency to get caught on items such as clothing; covering the hammer by removing the spur reduces this tendency.

The following are terms related to firearms and ammunition topics.

Multiple-barrel firearm Type of firearm with more than one barrel

A multiple-barrel firearm is any type of firearm with more than one gun barrel, usually to increase the rate of fire or hit probability and to reduce barrel erosion/overheating.

Safety (firearms) Feature on firearms to prevent accidental discharge

In firearms, a safety or safety catch is a mechanism used to help prevent the accidental discharge of a firearm, helping to ensure safer handling.

Recoil operation is an operating mechanism used to implement locked breech, autoloading firearms. Recoil operated firearms use the energy of recoil to cycle the action, as opposed to gas operation or blowback operation using the pressure of the propellant gas.

Repeating firearm

A repeating firearm, or repeater, is any firearm that is capable of being fired repeatedly before having to manually reload new ammunition into the weapon.

References

  1. "English Patents of Inventions, Specifications: 1858, 2958 - 3007". 1859.
  2. Briely Shotgun Conversion Sleeves Archived September 28, 2007, at the Wayback Machine