A stock, also known as a buttstock or shoulder stock, is present in many firearms and some crossbows (though a crossbow stock is properly a tiller). The stock provides a means for the shooter to firmly support the device and easily aim it. The stock also transmits recoil into the shooter's body.

History and etymology

The term stock in reference to firearms dates to 1571 is derived from the Germanic word stoc, 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.

Anatomy of a gunstock

A gunstock is broadly divided into two parts (see above). The rear portion is the butt (1) and front portion is the fore-end (2). The butt is further divided into the comb (3), heel (4), toe (5), and grip (6). The stock pictured is a thumbhole (7) style.

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 bolt action rifles. Two piece stocks use a separate piece for the butt and fore-end, such as that commonly found on break open 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.

Stock measurements

Stock measurement 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.

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. Due to the natural properties and variability in woods, stocks made from solid wood must take into account these properties. The grain of the wood determines the strength, and the grain should flow throgh the wrist of the stock and out the toe; having the grain perpendicular to these areas weakens the stock considerably.

Injection molded synthetic

While setup costs are high, once ready to produce, injection molding produces 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 the thermoplastic materials used for injection molding.

Hand-laid composite stocks

A hand laid composite stock, out of materials such as fiberglass, kevlar, and/or graphite cloth, saturated in an appropriate binder, into a mold. 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 proceess, machining in the inletting after the stock is finished, molding directly to the action as a separate process, or through the use of a machined metal component molded in place during manufacture. Finish is provided by a layer of gel coat applied to the mold before the cloth is laid up.

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

Legal issues

In some jurisdictions, the nature of the stock may impact the legal status of the firearm. Examples of this are:

• Adding a shoulder stock on a firearm with a barrel shorter than 16 inches (40.6 cm) makes it a short barreled rifle under the US National Firearms Act
• Folding stocks or stocks with separate pistol grips are qualifying features in the Federal Assault Weapons Ban, and in some state and local legislation modeled thereafter

Gallery

References