The meaning of GUNSTOCK
A gunstock or often simply stock, the back portion of which also known as a shoulder stock, a buttstock or simply a butt, is a part of a long gun that provides structural support, to which the barrel, action, and firing mechanism are 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 when shooting the gun, and helps to counter muzzle rise by transmitting recoil straight into the shooter’s body.
History and etymology
The term stock in reference to firearms dates to 1571 is derived from the Germanic word Stock, meaning tree trunk, referring to the wooden nature of the gunstock.
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. This greatly improved the accuracy of the arquebus, to a level that would not be surpassed until the advent of rifled barrels.
Ironically, the stocks of muskets introduced during the European colonization of the Americas were repurposed as hand-to-hand war clubs by Native Americans and First Nations when fragile accessories were damaged or scarce ammunition exhausted. Techniques for gunstock hand weapons are being revived by martial arts such as Okichitaw.
Anatomy of a gunstock
A gunstock is broadly divided into two parts (see above). The rear portion is the butt and front portion is the fore-end. The fore-end supports and affixes the receiver, and relays the recoil impulse from the barrel. The butt interacts with the shooter’s trigger hand while being braced against the shoulder for stability, and is further divided into the comb, heel, toe, and grip.
In some modern firearm designs, the lower receiver and handguard replace the fore-end stock, leaving only the butt portion for the stock.
Styles and features of stocks
The most basic breakdown of stock types is into one-piece and two-piece stocks. A one-piece stock is a single unit from butt to fore-end, such as that commonly found on conventional bolt-action rifles. Two-piece stocks use a separate piece for the butt and fore-end, such as that commonly found on break-action shotguns, and lever-action rifles and shotguns. Traditionally, two-piece stocks were easier to make, since finding a wood blank suitable for a long one-piece stock is harder than finding short blanks for a two-piece stock.
In traditional 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 optical 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.
Collapsable or folding stocks are often seen on military-grade carbines, SMG/PDWs and their civilian-derived versions. A collapsible (or telescoping) stock makes the weapon more compact for storage, carrying and concealment, and is usually deployed just before shooting for better control. A butt hook, which is an attachment to the butt of the gun that is put under the shooter’s arm to prevent the rifle from pivoting forward from the weight of the barrel is sometimes used in competitive rifle shooting. These stocks are also used on combat shotguns like the Franchi SPAS-12 to allow the stock to collapse when not in use.
The fore-ends tend to vary both in thickness, from the splinter fore-ends common on British side-by-side shotguns to the wide, flat bottomed beavertail fore-ends found on benchrest shooting guns, and in length, from the short AK-47 style to the long Mannlicher stock that runs all the way to the muzzle. Most common on sporting firearms is the half-stock, which extends roughly half the length of the barrel.
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.
- Sight line, A datum line along the line of sight, extending axially to all points necessary for shotgun stock reference measurements.
- Length of pull, the length measured from the butt of the stock to the trigger. Many newer stock desings 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).
- Drop at heel, the distance from the Sight line to the heel of the butt. Sometimes also called the height of the buttpad or buttplate height.
- Drop at comb, the distance from the Sight line 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 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 a line parallel to the bore line, referenced to zero degrees if pointing vertical to the ground.
- Bore line, A datum line concentric with the rifle 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.
- 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.
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.
Burst or automatic shoulder fired small arms can incorporate the “straight-line” recoil configuration. This layout places both the center of gravity and 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.
A bump stock utilizes the natural recoil motion of a semi-automatic rifle to facilitate rapid fire similar to an automatic firearm without requiring any modification of internal mechanisms to convert the firearm to an automatic weapon. It consists of a sliding stock with an attached support step in front of the trigger. Pushing forward on the barrel, or forward grip, causes the gun to slide forward in the stock, “bumping” the trigger against the trigger finger that rests on the support step, firing the gun. The gun then recoils, moving the trigger backward, away from the finger. Continued forward pressure on the barrel or forward grip returns the trigger to the finger, repeating the cycle. The amount of forward pressure controls the rate of fire, which can reach several hundred rounds per minute.
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.
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.
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.
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.