Stock (firearms)

Agunstockor often simplystock,the back portion of which is also known as ashoulder stock,abuttstock,or simply abutt,is a part of along gunthat providesstructural support,to which thebarrel,action,andfiring mechanismare attached. The stock also provides a means for the shooter to firmly brace the gun and easily aim with stability by being held against the user's shoulder whenshootingthe gun, and helps to countermuzzle riseby transmittingrecoilstraight into the shooter's body.

The anatomy of a gunstock on aRuger 10/22semi-automatic riflewith Fajen thumbhole silhouette stock. 1)butt,2)forend,3)comb,4)heel,5)toe,6)grip,7)thumbhole

The tiller of acrossbowis functionally the equivalent of the stock on a gun.

History and etymology

An early hand cannon, orgonne,supported by a simple stock

The termstockin reference to firearms dates to 1571 is derived from theGermanicwordStock,meaningtree trunk,referring to the wooden nature of the gunstock.

Earlyhand cannonsused 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 thearquebus,amatchlockwith 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 theslow 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.This greatly improved the accuracy of the arquebus, to a level that would not be surpassed until the advent ofrifled barrels.

Ironically, the stocks ofmusketsintroduced during theEuropean colonization of the Americaswere repurposed ashand-to-handwar clubsbyNative AmericansandFirst Nationswhen fragileaccessorieswere damaged or scarce ammunition exhausted. Techniques for gunstock hand weapons are being revived by martial arts such asOkichitaw.

Anatomy of a gunstock

A gunstock is broadly divided into two parts (see above), with the boundary roughly at where thetriggeris. The rear portion is thebutt(1), and front portion is thefore-end(2). The fore-end (orforestock,forearm) affixes and supports thereceiver,and relays therecoilimpulse from the barrel via arecoil lug.The butt (orbuttstock) is braced against the shooter's shoulder for stability and also interacts with the trigger hand, and is further divided into thecomb(3),heel(4),toe(5), andgrip(6). The stock pictured above has athumbhole(7) style grip,which allows a more ergonomic vertical hold for the user's hand.

In some modern firearm designs, thelower receiverandhandguardreplace the fore-end stock, leaving only the butt portion as the recognizable "stock", even though they serve the same function as the traditional fore-end.

Styles and features of stocks

M1 Garandrifle with one-piece wooden stock

SPAS-12 shotgunwith a skeletonized folding stock

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 conventionalbolt-action rifles.Two-piece stocks use separate pieces for the butt and fore-end, such as that commonly found onbreak-actionandlever-actionfirearms. Traditionally, two-piece stocks were easier to make, since finding a quality wood blank suitable for a long one-piece stock is harder than finding short blanks for a two-piece stock.

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 usingiron sights;and "American" type, which the heel remains horizontal from the grip to favor more precision-oriented shooting usingtelescopic sights.There are also in-between designs (such as theWeatherby Mark V) with a "halfway" heel drop where the front half of the buttstock stays leveled.

Collapsibleor folding stocks are often seen on militarycarbines,SMG/PDWs,their civilian-derived versions and somemachine pistols.A collapsible (or telescoping) stock makes the weapon shorter and more compact for storage, carrying and concealment, and can be deployed just before shooting for better control. A butt hook, which is an attachment to the butt of thegunthat is put under the shooter's arm to prevent the rifle from pivoting forward from the weight of thebarrelis sometimes used in competitive rifleshooting.These stocks are also used oncombat shotgunslike theFranchi SPAS-12to allow the stock to collapse when not in use.

Grip

Different styles of gunstock grips

Thegripis 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 thetang.Many grips have roughenedtexturesor even finger grooves engraved into the sides to increase the firmness of the shooter's hold. Some grips have athumb rest(or groove) carved near the tang to give a more ergonomic hold for the trigger finger.

The grip varies widely in styles. Astraight gripstock (A) proceeds smoothly from toe to the trigger, giving a nearly horizontal holding angle for the trigger hand, while a fullpistol gripstock (E) contains a separate stand-out grip piece, providing a nearly vertical angle for the trigger hand for maximalergonomics,and is commonly found on modern military rifles such as the ubiquitousAK-47andM16/M4families ofassault rifles.In between the two extremes, thesemi-gripstock (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.Anschützgripstocks (C), for example, use a nearly vertical grip, and manythumbhole gripstocks (D) are similar to pistol grips in shape.

Comb

Variations in gunstock combs

Athumbscrew-adjustable cheek rise

Thecombis 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'ssights,higher sights such as telescopic sights require higher combs.

The simplest form is astraightcomb (A), which is the default form seen in all traditional rifles with iron sights. TheMonte Carlocomb (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 roundeddomeshape, it is often called ahogbackcomb. Acheekpiece(C) is a raised section protruding from thesideof 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 raisedrollovercheekpiece (D) extending across the top of the stock to form essentially an exaggeratedly wide and high Monte Carlo comb.

Some modern buttstocks have a movable comb piece called acheek restorcheek rise,which offers adjustable comb height that tailors to the shooter's ergonomic preference.

Fore-end

Thefore-endstend to vary both in thickness, from thesplinterfore-ends common on Britishside-by-side shotgunsto the wide, flat bottomedbeavertailfore-ends found onbenchrest shootingguns, and in length, from the short AK-47 style to the longMannlicher stockthat runs all the way to the muzzle. Most common on sporting firearms is thehalf-stock,which extends roughly half the length of the barrel.

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 withshotguns,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.

• Sight line,adatum linealong theline 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 includelength to sight(LTS) andlength to handstop(LTH).
• 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.
  • 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.
• Bore line,A datum line concentric with thebarrel boreand 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 minimizemuzzle rise.
• 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.

Accuracy considerations

Main article:Accurizing

M16A1cutaway rifle (top) and M16A2 (below) with a "straight-line" stock configuration

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 asbeddingprovide the stability of a synthetic with the aesthetics of wood.

Burst or automatic shoulder fired small arms can incorporate the "straight-line" recoil configuration. This layout places both thecenter of gravityand the position of the shoulder stock nearly in line with the longitudinal axis of the barrel bore, a feature increasing controllability during burst or automatic fire.

Adjustability

AnM2010 Enhanced Sniper Riflein achassissystem with adjustable buttplate and cheekriser

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 betternatural 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 acheek riser) and/or buttplate, which use one or moreguide railsto control position changes. These moveable parts can be adjusted using aleadscrewusually turned with aknurled wheel,or have them slide freely along the guide rails and then fastened to desirable positions withset screwsorthumbscrews.Some more complex designs also allow horizontal shifting and tilting of the cheek riser, as well as vertical shifting and slanting of the buttplate.

Construction

Traditionally, stocks are made fromwood,generally a durable hardwood such aswalnut.A growing option is the laminated wood stock, consisting of many thin layers of wood bonded together at high pressures withepoxy,resulting in a dense, stable composite.

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 ofsteeloralloyfor strength and locking mechanisms, and wood or plastics for shape. Stocks forbullpuprifles must take into account the dimensions of the rifle's action, as well as ergonomic issues such as ejection.

Wood stocks

Gun stock construction on a lathe from the 1850s (photoc. 2015)

While walnut is the favored gunstock wood, many other woods are used, includingmaple,myrtle,birch,andmesquite.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.

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.

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 of1⁄16inch (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.

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, convincedSturm, Ruger,Savage Arms,andU.S. Repeating Arms Company(Winchester) to display some laminate stocks on their rifles in a green, brown and black pattern (often calledcamo). The response was overwhelming, and that marked the beginning of laminated stocks on production rifles.

Injection molded synthetic

While setup costs are high, once ready to produce,injection moldingproduces stocks for less than the cost of the cheapest wood stocks. Every stock is virtually identical in dimension, and requires no bedding, inletting, or finishing. The downsides are a lack of rigidity and thermal stability, which are side effects of thethermoplasticmaterials used for injection molding.

Hand-laid composite stocks

A hand-laid composite stock iscomposedout 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 ofgel coatapplied to the mold before the cloth is laid up.

Metallic

Some high production firearms (such as thePPS-43,MP-40,and theZastava M70B) make use of metal frames in order to have a thin but strong stock that can be folded away to make the weapon more compact. However, even a skeletonized steel stock is often heavier than the equivalent solid wooden stock. Consequentially, less cost-sensitive designs like theFN Minimimake use of lighter-than-steel materials such asaluminium alloyortitanium.A few designs, like theAccuracy International Arctic Warfare,use a metallicchassiswhich securelybedsthe functional components of the firearm, with non-structural polymer panels attached externally like ashellfor ergonomics and aesthetics.

Non-fixed stock

Telescoping stock

M4 carbine with a 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 arifle,submachine gun,shotgun,orlight machine gunto 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 andconcealable,or extend ( "deploy" ) it for better accuracy.

Some telescoping stocks, such as those on the M4 carbine andBenelli M4,have more than one length of pull setting, allowing the stock to be adjusted for different users.

Folding stock

AnAK-103with its stock folded

AnUzi submachine gunwith a double-articulated folding stock

Some buttstocks can have ahingedattachment 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 thecore;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

Main article:Bump stock

Abump stockallows semi-automatic firearms to shoot at a fasterrate of firethat somewhat mimics fully automatic fire.

Abump fire stockorbump stockutilizes therecoilof asemi-automatic rifleto facilitate a faster rate of fire without requiring any modification of internal mechanisms to convert the firearm to anautomatic firearm.

The term "bump fire" was originally an improvised technique to shoot anAR-15faster by having the shooter applying a non-rigid forward push on the receiver (by gripping the handguard or via a foregrip) and having a loose hold on the pistol grip. When the gun shoots, the recoil shifts the receiver backwards, moving the trigger conversely forward (from the receiver'sframe of reference) and relaxes the pulling force on the trigger, allowing it to reset. When the shooter's forward push overcomes the recoil momentum and shifts the receiver back towards the front, the trigger is "bumped" against the shooter's finger and gets depressed again, firing off another round, which produces another recoil that repeats the above process. This allows a cycling rate of firing much faster than what the shooter's own finger can typically achieve, but is usually inaccurate due to the shooter often having tofire from the hipto still hold the gun firmly.

Abump stockreplaces the manual forward push with aspringmechanism at the interface between the receiver and the pistol grip/buttstock. The user only has to simply hold the trigger back against the grip, and the spring-assisted forward push will itself work against the recoil to cycle the shooting. This allows an increased rate of fire that can reach several hundredrounds per minute,and is far more consistent in performance compared to the manual bump fire.

For handguns

The Luger Artillery Pistol with its wooden holster attached

TheCZŠkorpionwith its folding wire stock extended.

Manyhandgunsalso support the use of shoulder stocks to handle recoil. An example is theLuger P08"Artillery Pistol", which has a wooden factoryholsterthat can be attached to the pistol grip and used as an improvised buttstock. Someaftermarketmanufacturers also make accessories for popularsemi-automatic pistolssuch asGlocks,including grip modules that have built-on folding stocks, or even "conversion kits" that allow the pistol to be mounted into acarbine-shapedenclosurewith a shoulder stock.

Machine pistolssuch as theMAC-10,Micro-UziandŠkorpion vz. 61often use a folding skeleton stock that can be extended and braced during engagements to provide auto-fire stability.

Pistol brace

ASIG MPXwith a retractableVelcro-strap brace with twoslide rods

Apistol stabilizing brace(PSB) orarm braceis a device like a buttstock, but purportedly meant to be in contact with or wrap around the shooter'sforearmlike awrist braceorsplint,instead of being pressed against the shoulder, as an alternative measure of countering recoil and muzzle rise with one-handed shooting. Developed from an arm hook (introduced for the same reasons) on the collapsible stock of theFranchi SPAS-12shotgun, it is mainly designed for a category of guns which are marketed as "pistols" despite being much larger and heavier than typical pistols, having carbine-style receivers (e.g. "AR pistols" andPC Charger), and which are stockless out-of-factory to avoid being legally classified asshort-barreled rifles.The brace can be mounted onto the gun via an M4-style buffer tube, or via aPicatinny railinterface.

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.On December 18, 2020, theBureau of Alcohol, Tobacco, Firearms and Explosivesfiled a notice to theFederal RegistertitledObjective 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 theNational Firearms Act,but withdrew the notice five days later.

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 ashort-barreled rifle(SBR) under the United States National Firearms Act.
• Folding stocks, or stocks with separate pistol grips, are regarded asassault weaponfeatures and banned in some U.S. states and municipalities.
• In the United States, fitting abump stockto 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

• 
  SIG 550rifle with folding stock
• 
  Colt Army Model 1860revolverwith a wooden detachable stock
• 
  Ruger 10/22International with full lengthMannlicher-style stock
• 
  AK-47with a three piece stock consisting of butt, grip and fore-end
• 
  Storage compartment inside a buttstock with opened trapdoor

See also

• Vertical forward grip

External links

• Media related toStock (firearm)at Wikimedia Commons
• Close combat butt stock with blade for assault rifles