Stock (firearms)
A gunstock or often simply stock, the back portion of which is also known as a shoulder stock, a buttstock, or simply a butt, is a part of a
The tiller of a crossbow is functionally the equivalent of the stock on a gun.[2]
History and etymology
The term stock in reference to firearms dates to 1571 is derived from the
Early hand cannons used a simple stick fitted into a socket in the breech end to provide a handle. The modern gunstock shape began to evolve with the introduction of the arquebus, a matchlock with a longer barrel and an actual lock mechanism, unlike the hand-applied match of the hand cannon. Firing a hand cannon requires careful application of the match while simultaneously aiming; the use of a matchlock handles the application of the slow match, freeing up a hand for support. With both hands available to aim, the arquebus could be braced with the shoulder, giving rise to the basic gunstock shape that has survived for over 500 years.[4] This greatly improved the accuracy of the arquebus, to a level that would not be surpassed until the advent of rifled barrels.[5]
Ironically, the stocks of
Anatomy of a gunstock
A gunstock is broadly divided into two parts (see above), with the boundary roughly at where the trigger is. The rear portion is the butt (1), and front portion is the fore-end (2). The fore-end (or forestock, forearm) affixes and supports the receiver, and relays the recoil impulse from the barrel via a recoil lug. The butt (or buttstock) is braced against the shooter's shoulder for stability and also interacts with the trigger hand, and is further divided into the comb (3), heel (4), toe (5), and grip (6). The stock pictured above has a thumbhole (7) style grip,[8] which allows a more ergonomic vertical hold for the user's hand.
In some modern firearm designs, the
Styles and features of stocks
The most basic categorization of stock types is into one-piece and two-piece stocks. In a one-piece stock, the butt and fore-end are a continuous monolithic piece, such as that commonly found on conventional
In one-piece rifle stocks, the butt also varies in styles between the "European" type, which has a drop at the heel to favor quick shooting using iron sights; and "American" type, which the heel remains horizontal from the grip to favor more precision-oriented shooting using telescopic sights. There are also in-between designs (such as the Weatherby Mark V) with a "halfway" heel drop where the front half of the buttstock stays leveled.
Grip
The grip is at the front portion of the butt that connects with the fore-end, and is held by the shooter's trigger hand during firing. The back surface of butt front near the grip is called the tang. Many grips have roughened
The grip varies widely in styles. A straight grip stock (A) proceeds smoothly from toe to the trigger, giving a nearly horizontal holding angle for the trigger hand, while a full pistol grip stock (E) contains a separate stand-out grip piece, providing a nearly vertical angle for the trigger hand for maximal ergonomics, and is commonly found on modern military rifles such as the ubiquitous AK-47 and M16/M4 families of assault rifles. In between the two extremes, the semi-grip stock (B) is perhaps the most common sporting rifle stock, with a steeper angle cut into the stock to provide a more diagonal angle for the trigger hand. Modern target-style stocks have generally moved towards a fuller, more vertical grip, though built into the stock rather than made as a separate piece. Anschütz grip stocks (C), for example, use a nearly vertical grip, and many thumbhole grip stocks (D) are similar to pistol grips in shape.
Comb
The comb is another area of wide variation. Since the comb must support the shooter's cheek at a height that steadily aligns the aiming eye with the weapon's sights, higher sights such as telescopic sights require higher combs.
The simplest form is a straight comb (A), which is the default form seen in all traditional rifles with iron sights. The Monte Carlo comb (B) is commonly found on stocks designed for use with scopes, and features an elevated comb to lift the cheek higher, while keeping the heel of the stock low. If the elevated comb is of a rounded dome shape, it is often called a hogback comb. A cheekpiece (C) is a raised section protruding from the side of the stock, which provides a more conformed support for the shooter's cheek. There is some confusion between these terms, as the features are often combined, with the raised rollover cheekpiece (D) extending across the top of the stock to form essentially an exaggeratedly wide and high Monte Carlo comb.[8][10][11]
Some modern buttstocks have a movable comb piece called a cheek rest or cheek rise, which offers adjustable comb height that tailors to the shooter's ergonomic preference.
Fore-end
The fore-ends tend to vary both in thickness, from the splinter fore-ends common on British
Stock measurements
Stock measurements are important regarding target rifle stocks if competing in IBS or NBRSA registered matches. The target rifle stocks must meet certain dimensional and configuration criteria according to the class of competition engaged in. Stock dimensioning is especially important with shotguns, where the typical front-bead-only sight requires a consistent positioning of the shooter's eye over the center of the barrel for good accuracy. When having a stock custom built or bent to fit, there are a number of measurements that are important.[8][13]
- Sight line, a line of visual aim, extending axially to all points necessary for shotgun stock reference measurements.
- Length of pull, the length measured from the back end of the butt to the trigger. Many newer stock designs have an adjustable length of pull. Other relevant length measurements affected by the length of pull include length to sight (LTS) and length to handstop (LTH).[14]
- Drop at heel, the distance from the sightline to the heel of the butt. Sometimes also called the height of the buttpad or buttplate height.
- Drop at comb, the distance from the sightline to the comb. Sometimes also called the height of the cheek rest or cheekpiece height.
- Cast is sometimes also called offset.[14]
- Cast off, the distance from the center of the butt to the Sight line, to the right side as seen from the rear. Often used by those shooting from the right shoulder.
- Cast on, the distance from the center of the butt to the Sight line, to the left side as seen from the rear. Often used by those shooting from the left shoulder.
- Pitch, the vertical angle of the butt of the stock, determined by a straight line from heel to toe, referenced perpendicular to the Sight line.
- Cant, the angle of the butt of the stock, rotated around an axis parallel to the bore line, referenced to zero degrees if pointing vertical to the ground.[14]
- Bore line, A datum line concentric with the barrel bore and extending axially to all points necessary for rifle stock reference measurements.
- Recoil arm, the vertical distance between the bore axis and the contact point of the stock against the shoulder where the recoil acts. If the recoil line corresponds to the bore line, the firearm can recoil straight backwards and minimize muzzle rise.[15]
- Corporal line, the bottom edge of the butt of the stock, or as determined by a straight line from grip to toe.
- Corporal angle, the angle of the corporal line referenced to the bore line at the corporal intercept point.
- Corporal intercept point, the point on the bore line forward of the bolt face where (if) the corporal line intercepts the bore line.
- Handguard rotation, only found on firearms where the handguard can be rotated.[14]
Accuracy considerations
In addition to ergonomic issues, the stock can also have a significant impact on the accuracy of the rifle. The key factors are:
- A secure fit between the stock and action, so that the rifle does not shift under recoil
- A stable material, that does not suffer from changes in shape with temperature, humidity, or other environmental conditions to a degree that could adversely impact accuracy
A well designed and well built wooden stock can provide the secure, stable base needed for an accurate rifle, but the properties of wood make it more difficult than more stable synthetic materials. Wood is still a top choice for aesthetic reasons, however, and solutions such as bedding provide the stability of a synthetic with the aesthetics of wood.[16][17]
Burst or automatic shoulder fired small arms can incorporate the "straight-line" recoil configuration. This layout places both the
Adjustability
Traditional gunstocks have a permanently-shaped buttstock that is fixed in length of pull and comb height, and cannot tailor to the anatomical variation between different users. If the user wants a more comfortable head position to achieve better natural point of aim, then an additional cheek pad (which add to the comb height) or a thicker buttplate (which add to the length of pull) need to be installed. These improvisations might not be ideal as they might still not achieve optimal fitting to a person's ergonomics.
Modern manufacturing and gunsmithing techniques can produce gunstocks with variable comb heights and buttplate positions. This can be achieved either by having interchangeable modules or using spacer blocks, which can increase the vertical and horizontal thickness. Alternatively, the buttstock can be built with a movable comb (known as a cheek riser) and/or buttplate, which use one or more
Construction
Traditionally, stocks are made from wood, generally a durable hardwood such as walnut. A growing option is the laminated wood stock, consisting of many thin layers of wood bonded together at high pressures with epoxy, resulting in a dense, stable composite.[17][16]
Regardless of the material actually employed, the general term "furniture" is often applied to gunstocks by curators, researchers and other firearm experts.
Folding, collapsible, or removable stocks tend to be made from a mix of steel or alloy for strength and locking mechanisms, and wood or plastics for shape. Stocks for bullpup rifles must take into account the dimensions of the rifle's action, as well as ergonomic issues such as ejection.
Wood stocks
While walnut is the favored gunstock wood, many other woods are used, including maple, myrtle, birch, and mesquite. In making stocks from solid wood, one must take into account the natural properties and variability of woods. The grain of the wood determines the strength, and the grain should flow through the wrist of the stock and out the toe; having the grain perpendicular to these areas weakens the stock considerably.[16]
In addition to the type of wood, how it is treated can have a significant impact on its properties. Wood for gunstocks should be slowly dried, to prevent grain collapse and splitting, and also to preserve the natural color of the wood; custom stockmakers will buy blanks that have been dried two to three years and then dry it for several additional years before working it into a stock. Careful selection can yield distinctive and attractive features, such as crotch figure, feathering, fiddleback, and burl, which can significantly add to the desirability of a stock. While a basic, straight grained blank suitable for a utilitarian stock might sell for US$20, an exhibition grade blank with superb figure could price in the range of US$2000. Blanks for one piece stocks are more expensive than blanks for two piece stocks, due to the greater difficulty in finding the longer blanks with desirable figure. Two piece stocks are ideally made from a single blank, so that the wood in both parts shows similar color and figure.[18]
Laminated wood
Laminated wood consists of two or more layers of wood, impregnated with glue and attached permanently to each other. The combination of the two pieces of wood, if laid out correctly, results in the separate pieces moderating the effects of changes in temperature and humidity. Modern laminates consist of 1⁄16 inch (1.6 mm) thick sheets of wood, usually birch, which are impregnated with epoxy, laid with alternating grain directions, and cured at high temperatures and pressures. The resulting composite material is far stronger than the original wood, free from internal defects, and nearly immune to warping from heat or moisture. Typically, each layer of the laminate is dyed before laminating, often with alternating colors, which provides a pattern similar to wood grain when cut into shape, and with bright, contrasting colors, the results can be very striking. The disadvantage of laminate stocks is density, with laminates weighing about 4 to 5 ounces (110 to 140 g) more than walnut for a typical stock.[17]
While wood laminates have been available for many years on the custom market (and, in subdued form, in some military rifles), in 1987 Rutland Plywood, a maker of wood laminates, convinced
Injection molded synthetic
While setup costs are high, once ready to produce,
Hand-laid composite stocks
A hand-laid composite stock is composed out of materials such as fiberglass, Kevlar, graphite cloth, or some combination, saturated in an appropriate binder, placed into a mold to set, or solidify. The resulting stock is stronger and more stable than an injection-molded stock. It can also be as little as half the weight of an injection-molded stock. Inletting and bedding can be accomplished by molding in as part of the manufacturing process, machining in the inletting after the stock is finished, molding directly to the action as a separate process, or molding a machined metal component in place during manufacture. Finish is provided by a layer of
Metallic
Some high production firearms (such as the
Non-fixed stock
Telescoping stock
A telescoping stock (alternatively collapsible stock) is a buttstock that can retract into and shorten itself (telescoping) in order to make the whole weapon more compact. Telescoping stocks are useful in allowing a rifle, submachine gun, shotgun, or light machine gun to be stored or maneuvered in places it would otherwise have trouble fitting. The user can either slide in ("collapse") the buttstock to render the weapon more portable and concealable, or extend ("deploy") it for better accuracy.
Some telescoping stocks, such as those on the M4 carbine and Benelli M4, have more than one length of pull setting, allowing the stock to be adjusted for different users.
Folding stock
Some buttstocks can have a hinged attachment to the receiver and can be folded forward to shorten the overall length of the gun. The hinge usually has a locking mechanism to prevent accidental or unwanted movements of the buttstock. When stability is not needed, the gun can be folded down to save space, be concealed, or held with one hand or nearer to the core; when stable aim is needed, the buttstock can be quickly extended and held to the shoulder.
Most folding stocks bend left or right depending on factory design or user preferences. Some are however designed to bend up and down, and usually made of a minimalistic "skeletonized" frame to fit over and envelop the receiver. Some compact weapons (e.g. machine pistols) have foldable buttstocks with more than one articulations to allow even more shortening.
Bump stock
A bump fire stock or bump stock utilizes the recoil of a semi-automatic rifle to facilitate a faster rate of fire without requiring any modification of internal mechanisms to convert the firearm to an automatic firearm.
The term "bump fire" was originally an improvised technique to shoot an
A
For handguns
Many
Pistol brace
A pistol stabilizing brace (PSB) or arm brace is a device like a buttstock, but purportedly meant to be in contact with or wrap around the shooter's
The bulkier end of a brace can still be leaned against the shoulder like a shoulder stock, but these devices are marketed as being intended for attachment to the arm to circumvent the legal restrictions that would arise from calling them shoulder stocks.[19] On December 18, 2020, the Bureau of Alcohol, Tobacco, Firearms and Explosives filed a notice to the Federal Register titled Objective Factors for Classifying Weapons with "Braces", proposing a series of criteria used to evaluate whether pistols with attached stabilizing braces are firearms that should be regulated by the National Firearms Act,[20] but withdrew the notice five days later.[21]
Legal issues
In some jurisdictions, the nature of the stock may change the legal status of the firearm. Examples of this are:
- Adding a shoulder stock to a firearm with a barrel shorter than 16 inches (41 cm) changes it into a short-barreled rifle (SBR) under the United States National Firearms Act.
- Folding stocks, or stocks with separate pistol grips, are regarded as assault weapon features and banned in some U.S. states and municipalities.
- In the United States, fitting a bump stock to a semi-automatic firearm causes it to be classified as a machine gun by the Bureau of Alcohol, Tobacco, Firearms and Explosives, meaning they are effectively banned on the federal level. They are also banned in Canada and the United Kingdom.
Gallery
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SIG 550rifle with folding stock
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Colt Army Model 1860 revolver with a wooden detachable stock
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Mannlicher-style stock
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AK-47 with a three piece stock consisting of butt, grip and fore-end
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Storage compartment inside a buttstock with opened trapdoor
See also
References
- ^ Chuck Hawks. "Rifle Recoil".
- ^ "Online Etymology Dictionary, tiller".
- ^ "Online Etymology Dictionary, stock".
- ^ "Handgonne". Archived from the original on 2016-10-14. Retrieved 2008-01-03.
- ^ Krenn, Peter (1991). "Test-Firing Selected 16th to 18th C. Weapons". Military Illustrated. 33.
- ^ "Pitt Rivers Museum". Archived from the original on 2008-09-21.
- ^ "British Museum". Archived from the original on 2010-01-21.
- ^ a b c d e "SAAMI Glossary, S". Archived from the original on 2007-10-31. Retrieved 2008-01-03.
- ^ Targetshooting.ca Archived 2007-10-11 at the Wayback Machine
- ^ "Rifle Stock Terms". 7 December 2006.
- ^ "SAAMI Glossary, C". Archived from the original on 2008-04-09.
- ^ "SAAMI Glossary, F". Archived from the original on 2018-05-18. Retrieved 2008-01-03.
- ^ "The Magic of Cast-off".
- ^ a b c d Configuring the Eliseo Tubegun Stock within AccurateShooter.com
- ^ a b Senich, Peter: The German Assault Rifle: 1935–1945, page 239. Paladin Press, 1987.
- ^ a b c Larry Lyons. "The Semi-Synthetic Solution". Guns & Ammo. Archived from the original on October 23, 2007.
- ^ a b c d e f Jon R. Sundra (November 1999). "The Stock Market". Guns Magazine.
- ^ Ron Swartley (October 1990). "Gunstock blanks: how to buy the best - gunsmithing tips". Shooting Industry.
- ^ Kingery, Max M. "OPEN LETTER ON THE RESIGN OF "STABILIZING BRACES"" (PDF).
- ^ "Objective Factors for Classifying Weapons with "Stabilizing Braces"". Federal Register. 2020-12-18. Retrieved 2020-01-12.
- ^ "SB Criteria Withdrawal Notice". Bureau of Alcohol, Tobacco, Firearms and Explosives. 2020-12-23. Retrieved 2020-01-12.
External links
- Media related to Stock (firearm) at Wikimedia Commons
- Close combat butt stock with blade for assault rifles