bolt-action

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 (as most users are right-handed).

Most bolt-action firearms use a rotating bolt design, where the handle must first be rotated upward to unlock the bolt from the receiver, then pulled back to open the breech and allowing any spent cartridge case to be extracted and ejected. This also cocks the striker within the bolt (either on opening or closing of the bolt depending on the gun design) and engages it against the sear. When the bolt is returned to the forward position, a new cartridge (if available) is pushed out of the magazine and into the barrel chamber, and finally the breech is closed tight by rotating the handle down so the bolt head relocks on the receiver.

Bolt-action firearms are generally repeating firearms, but some single-shot breechloaders also use bolt-action design as a breechblock mechanism. The majority of these firearms are rifles, but there are some bolt-action variants of shotguns and handguns as well. Examples of these 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, bolt-action rifles were the standard infantry service weapons for most of the world's military forces. In modern military and law enforcement, bolt-action firearms have been mostly replaced by semi-automatic and selective-fire firearms, and have remained prevalent only as sniper rifles due to the design's inherent potential for superior accuracy and precision, as well as ruggedness and reliability compared to autoloading designs.

History

The first bolt-action rifle was produced in 1824 by Johann Nikolaus von Dreyse, following work on breechloading rifles that dated to the 18th century. Von Dreyse would perfect his ''Nadelgewehr'' (Needle Rifle) by 1836, and it was adopted by the Prussian Army in 1841. While it saw limited service in the German Revolutions of 1848, it was not fielded widely until the 1864 victory over Denmark. In 1850 a metallic centerfire bolt-action breechloader was patented by Béatus Beringer. In 1852 another metallic centerfire bolt-action breechloader was patented by Joseph Needham and improved upon in 1862 with another patent. Two different systems for primers –the mechanism to ignite a metallic cartridge's powder charge – were invented in the 1860s as well, the Berdan and the Boxer systems.

The United States purchased 900 Greene rifles (an under hammer, percussion capped, single-shot bolt-action that used paper cartridges and an ogival bore rifling system) in 1857, which saw service at the Battle of Antietam in 1862, during the American Civil War; however, this weapon was ultimately considered too complicated for issue to soldiers and was supplanted by the Springfield Model 1861, a conventional muzzle loading rifle. During the American Civil War, the bolt-action Palmer carbine was patented in 1863, and by 1865, 1000 were purchased for use as cavalry weapons. The French Army adopted its first bolt-action rifle, the Chassepot rifle, in 1866 and followed with the metallic cartridge bolt-action Gras rifle in 1874.

European armies continued to develop bolt-action rifles through the latter half of the 19th century, first adopting tubular magazines as on the Kropatschek rifle and the Lebel rifle. The first bolt-action repeating rifle was patented in Britain in 1855 by an unidentified inventor through the patent agent Auguste Edouard Loradoux Bellford using a gravity-operated tubular magazine in the stock. Another more well-known bolt-action repeating rifle was the Vetterli rifle of 1867 and the first bolt-action repeating rifle to use centerfire cartridges was the weapon designed by the Viennese gunsmith Ferdinand Fruwirth in 1871. Ultimately, the military turned to bolt-action rifles using a box magazine; the first of its kind was the M1885 Remington–Lee, but the first to be generally adopted was the British 1888 Lee–Metford. World War I marked the height of the bolt-action rifle's use, with all of the nations in that war fielding troops armed with various bolt-action designs.

During the buildup prior to World War II, the military bolt-action rifle began to be superseded by semi-automatic rifles and later fully automatic rifles, though bolt-action rifles remained the primary weapon of most of the combatants for the duration of the war; and many American units, especially the USMC, used bolt-action M1903 Springfields until sufficient numbers of M1 Garands were made available. The bolt-action is still common today among sniper rifles, as the design has the potential for superior accuracy, reliability, lesser weight, and the ability to control loading over the faster rate of fire that alternatives allow. There are, however, many semi-automatic sniper rifle designs, especially in the designated marksman role.

Today, bolt-action rifles are chiefly used as hunting rifles. These rifles can be used to hunt anything from vermin to deer and to large game, especially big game caught on a safari, as they are adequate to deliver a single lethal shot from a safe distance.

Bolt-action shotguns are considered a rarity among modern firearms but were formerly a commonly used action for .410 entry-level shotguns, as well as for low-cost 12- gauge shotguns. The M26 Modular Accessory Shotgun System (MASS) is the most advanced and recent example of a bolt-action shotgun, albeit one designed to be attached to an M16 rifle or M4 carbine using an underbarrel mount (although with the standalone kit, the MASS can become a standalone weapon). Mossberg 12-gauge bolt-action shotguns were briefly popular in Australia after the 1997 changes to firearms laws, but the shotguns themselves were awkward to operate and had only a three-round magazine, thus offering no practical and real advantages over a conventional double-barrel shotgun.

Some pistols use a bolt-action, although this is uncommon, and such examples are typically specialized target handguns.

Major bolt-action systems

Rotating bolt

Most of the bolt-action designs use a rotating bolt (or "turn pull") design, which involves the shooter doing an upward "rotating" movement of the handle to unlock the bolt from the breech and cock the firing pin, followed by a rearward "pull" to open the breech, extract the spent cartridge case, then reverse the whole process to chamber the next cartridge and relock the breech. There are four major turn bolt-action designs: the Remington M-700, possibly the single most numerous produced rifle in history which is now also used as basis for most custom competition rifle actions, along with the Mauser system, the Lee–Enfield system, and the Mosin–Nagant system. All four differ in the way the bolt fits into the receiver, how the bolt rotates as it is being operated, the number of locking lugs holding the bolt in place as the gun is fired, and whether the action is cocked on the opening of the bolt (as in both the Mauser system and the Mosin Nagant system) or the closing of the bolt (as in the Lee–Enfield system). The vast majority of modern bolt-action rifles were made for the commercial market post-war, numbering in the tens of millions by Remington in the unique, and most accurate Model 700, two of the others use the Mauser system, with other designs such as the Lee–Enfield system and the Mosin Nagant system, of only limited usage.

Mauser

The Mauser bolt-action system is based on 19th-century Mauser bolt-action rifle designs and was finalized in the Gewehr 98 designed by Paul Mauser. It is the most common bolt-action system in the world, being in use in nearly all modern hunting rifles and the majority of military bolt-action rifles until the middle of the 20th century. The Mauser system is stronger than that of the Lee–Enfield due to two locking lugs just behind the bolt head, which make it better able to handle higher-pressure cartridges (i.e. magnum cartridges). The 9.3×64mm Brenneke and 8×68mm S magnum rifle cartridge "families" were designed for the Mauser M 98 bolt-action. A novel safety feature was the introduction of a third locking lug present at the rear of the bolt that normally did not lock the bolt, since it would introduce asymmetrical locking forces. The Mauser system features "cock on opening", meaning the upward rotation of the bolt when the rifle is opened cocks the action. A drawback of the Mauser M 98 system is that it cannot be cheaply mass-produced very easily. Many Mauser M 98-inspired derivatives feature technical alterations, such as omitting the third safety locking lug, to simplify production.

The controlled-feed Mauser M 98 bolt-action system's simple, strong, safe, and well-thought-out design inspired other military and hunting/sporting rifle designs that became available during the 20th century, including the:
* Gewehr 98/ Standardmodell/ Karabiner 98k
* M24 series
* vz. 24/ vz. 33
* Type 24 rifle
* M1903 Springfield
* Pattern 1914 Enfield
* M1917 Enfield
* Arisaka Type 38/ Type 99
* M48 Mauser
*Kb wz. 98a/ Karabinek wz. 1929
* FR8
*modern hunting/sporting rifles like the CZ 550, Heym Express Magnum, Winchester Model 70 and the Mauser M 98
*modern sniper rifles like the Sako TRG, Accuracy International Arctic Warfare and GOL Sniper Magnum

Versions of the Mauser action designed prior to the Gewehr 98's introduction, such as that of the Swedish Mauser rifles and carbines, lack the third locking lug and feature a "cock on closing" operation.

Lee–Enfield

The Lee–Enfield bolt-action system was introduced in 1889 with the Lee–Metford and later Lee–Enfield rifles (the bolt system is named after the designer James Paris Lee and the barrel rifling after the Royal Small Arms Factory at the London Borough of Enfield), and is a "cock on closing" action in which the forward thrust of the bolt cocks the action. This enables a shooter to keep eyes on sights and targets uninterrupted by cycling the bolt. The ability of the bolt between lugs and chamber to flex also keeps the shooter safer in case of catastrophic chamber overpressure. The disadvantage of the rearward-located bolt lugs is that a larger part of the receiver, between chamber and lugs, must be made stronger and heavier to resist stretching forces. Also, the bolt ahead of the lugs may flex on firing which, although a safety advantage, may eventually lead to increased head space. Repeated firing over time can lead to receiver "stretch" and excessive headspace, which if perceived as a problem can be remedied by changing the removable bolt head to a larger sized one (the Lee–Enfield bolt manufacture involved a mass production method where at final assembly the bolt body was fitted with one of three standard size bolt heads for correct headspace). In the years leading up to WWII, the Lee–Enfield bolt system was used in numerous commercial sporting and hunting rifles manufactured by such firms in the UK as BSA, LSA, and Parker–Hale, as well as by SAF Lithgow in Australia. Vast numbers of ex-military SMLE Mk III rifles were sporterised post WWII to create cheap, effective hunting rifles, and the Lee–Enfield bolt system is used in the M10 and No 4 Mk IV rifles manufactured by Australian International Arms. Rifle Factory Ishapore of India manufactures a hunting and sporting rifle chambered in .315 which also employs the Lee Enfield action.

*Lee–Enfield (all marks and models)
*Ishapore 2A1
*Various hunting/sporting rifles manufactured by BSA, LSA, SAF Lithgow, and Parker Hale
*Australian International Arms M10 and No 4 Mk IV hunting/sporting rifles
*Rifle Factory Ishapore's hunting Lee Enfield rifle in .315

Mosin–Nagant

The Mosin–Nagant action, created in 1891 and named after the designers Sergei Mosin and Léon Nagant, differs significantly from the Mauser and Lee–Enfield bolt-action designs. The Mosin–Nagant design has a separate bolthead that rotates with the bolt and the bearing lugs, in contrast to the Mauser system where the bolthead is a non-removable part of the bolt. The Mosin–Nagant is also unlike the Lee–Enfield system where the bolthead remains stationary and the bolt body itself rotates. The Mosin–Nagant bolt is a somewhat complicated affair, but is extremely rugged and durable; like the Mauser, it uses a "cock on open" system. Although this bolt system has been rarely used in commercial sporting rifles (the Vostok brand target rifles being the most recognized) and never outside of Russia, large numbers of military surplus Mosin–Nagant rifles have been sporterized for use as hunting rifles in the years since WWII.

Other designs

Both the U.S. Army's M24 Sniper Weapon System and U.S. Marine Corps' M40 sniper rifles are built from the Remington Model 700 rifle, in different degrees of modification, the main difference being the custom fitted heavy contour barrel and action length. The M24 utilizes the Long action and the M40 employs the short action bolt-face. The reason for this is that the M24 was originally intended to chamber the longer .300 Winchester Magnum round. The M40, however, was not intended to be chambered in the more powerful .300 Winchester Magnum round, yet the Marine Corps' intention was to migrate to the .300 Winchester Magnum cartridge. The Marine Corps' delay has led to a change in migratory direction, the current goal is for the M40 to become a rifle chambered in .338 Lapua Magnum.

The United States Army's Joint Munitions and Lethality Contracting Center has awarded Remington a Firm Fixed Price (FFP) Indefinite Delivery/ Indefinite Quantity (ID/IQ) contract (W15QKN-10-R-0403) for the upgrade of up to 3,600 M24 Sniper Weapon Systems (SWS) currently fielded to the Army pending type classification as the “M24E1”. The major configuration change for this system is the caliber conversion from 7.62mm NATO (.308 Winchester) to .300 Winchester Magnum to provide soldiers with additional precision engagement capability and range. The contract is for a five-year period and has a guaranteed minimum value of $192K with a potential value of up to $28.2 million. This award follows a full and open competitive evaluation lasting nine months, which began with the release of the Army's Request for Proposal (RFP) on January 13, 2010. The program will be executed under the authority of Project Manager Soldier Weapons, Picatinny Arsenal, NJ, and managed by its subordinate unit, Product Manager Individual Weapons. In 2009 the U.S. Army has changed the weapon name from M24E1 to the XM2010 Enhanced Sniper Rifle.

The Vetterli rifle was the first bolt-action repeating rifle introduced by an army. It was used by the Swiss army from 1869 to circa 1890. Modified Vetterlis were also used by the Italian Army. Another notable design is the Norwegian Krag–Jørgensen, which was used by Norway, Denmark, and briefly the United States. It is unusual among bolt-action rifles in that is loaded through a gate on the right side of the receiver, and thus can be reloaded without opening the bolt. The Norwegian and Danish versions of the Krag have two locking lugs, while the American version has only one. In all versions, the bolt handle itself serves as an emergency locking lug. The Krag's major disadvantage compared to other bolt-action designs is that it is usually loaded by hand, one round at a time, although a box-like device was made that could drop five rounds into the magazine, all at once via a stripper or en bloc clip. This made it slower to reload than other designs which used stripper or en bloc clips. Another historically important bolt-action system was the Gras system, used on the French Mle 1874 Gras rifle, Mle 1886 Lebel rifle (which was the first to introduce ammunition loaded with nitrocellulose-based smokeless powder), and the Berthier series of rifles.

Straight pull

Straight-pull bolt-actions differ from conventional turn-pull bolt-action mechanisms in that the bolt can be cycled back and forward without rotating the handle and thus only a linear motion is required, as opposed to a traditional bolt-action, where the user has to axially rotate the bolt in addition to the linear motions to perform chambering and primary extraction. The bolt locking of a straight pull action is achieved differently without needing manual inputs, therefore the entire operating cycle needs the shooter to perform only two movements (pull back and push forward) instead of four (rotate up, pull back, push forward, and rotate down), greatly increasing the gun's rate of fire