A bolt or quarrel is a

dart Dart or DART may refer to: * Dart, the equipment in the game of darts Arts, entertainment and media * Dart (comics), an Image Comics superhero * Dart, a character from ''G.I. Joe'' * Dart, a ''Thomas & Friends'' railway engine character * Dar ...

-like

projectile A projectile is an object that is propelled by the application of an external force and then moves freely under the influence of gravity and air resistance. Although any objects in motion through space are projectiles, they are commonly found in ...

used by

crossbow A crossbow is a ranged weapon using an elastic launching device consisting of a bow-like assembly called a ''prod'', mounted horizontally on a main frame called a ''tiller'', which is hand-held in a similar fashion to the stock of a long fi ...

s. The name "quarrel" is derived from the French word ''carré'', meaning square, referring to their typically square heads. Although their lengths vary, bolts are typically shorter and heavier than traditional

arrow An arrow is a fin-stabilized projectile launched by a bow. A typical arrow usually consists of a long, stiff, straight shaft with a weighty (and usually sharp and pointed) arrowhead attached to the front end, multiple fin-like stabilizers c ...

s shot with longbows.

Parts of the bolt

Point

The point, also called the ''head'' or the ''tip'', is the pointed and weighted front end of the bolt, which is sharp and hard so that it can penetrate the target.

Shaft

The shaft is the main body of the bolt to which other parts of the bolt are attached. In modern times it is normally made of

carbon fibre Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers (Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon compo ...

aluminium alloy An aluminium alloy (or aluminum alloy; see spelling differences) is an alloy in which aluminium (Al) is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon, tin, nickel and zinc. There are two principal ...

(or sometimes both aluminum and carbon fibre are used), and is very lightweight for its

strength Strength may refer to: Physical strength *Physical strength, as in people or animals * Hysterical strength, extreme strength occurring when people are in life-and-death situations *Superhuman strength, great physical strength far above human c ...

. Shafts come with varying degrees of

stiffness Stiffness is the extent to which an object resists deformation in response to an applied force. The complementary concept is flexibility or pliability: the more flexible an object is, the less stiff it is. Calculations The stiffness, k, of a b ...

— referred to as the " spine" of the bolt. The more resistant to bending a bolt is, the more "spine" it is said to have, and a crossbow with higher

draw Draw, drawing, draws, or drawn may refer to: Common uses * Draw (terrain), a terrain feature formed by two parallel ridges or spurs with low ground in between them * Drawing (manufacturing), a process where metal, glass, or plastic or anything ...

weight ideally needs to be paired with a heavier bolt point and higher spine specifications. The weight of a shaft is usually in

grain A grain is a small, hard, dry fruit (caryopsis) – with or without an attached hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and legum ...

s, and product descriptions may provide the total weight in grains, or in grains per inch (GPI), for which the total weight of shaft can be calculated by multiplying the GPI value with length of shaft in inches.

Fletching

Fletchings, also referred to as ''vanes'', are

fin A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluids. Fin ...

s located at the rear end of the shaft just before the nock. The fletching is typically made from soft light materials such as

feather Feathers are epidermal growths that form a distinctive outer covering, or plumage, on both avian (bird) and some non-avian dinosaurs and other archosaurs. They are the most complex integumentary structures found in vertebrates and a premier ...

plastic Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptab ...

silicone rubber Silicone rubber is an elastomer (rubber-like material) composed of silicone—itself a polymer—containing silicon together with carbon, hydrogen, and oxygen. Silicone rubbers are widely used in industry, and there are multiple formulations ...

. They stabilize the trajectory of the bolt via three different means: resisting pitching and yawing of the shaft by acting like a stabilizer fin (fin-stabilization); reducing deviation from the longitudinal axis by creating a back-pulling center of pressure behind the bolt's

center of mass In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may ...

( drag-stabilization); and in some particular cases, creating a

rotation Rotation, or spin, is the circular movement of an object around a '' central axis''. A two-dimensional rotating object has only one possible central axis and can rotate in either a clockwise or counterclockwise direction. A three-dimensional ...

around the longitudinal axis (spin-stabilization) by having the fletchings mounted at a slight

angle of attack In fluid dynamics, angle of attack (AOA, α, or \alpha) is the angle between a reference line on a body (often the chord line of an airfoil) and the vector representing the relative motion between the body and the fluid through which it is m ...

. There is no rule or formula for determining the length of fletching needed — generally the longer the shaft is, the longer the fletching needs to be, and vice versa.

Nock

nock Nock may refer to: Archery * In a bow and arrow, two notches near the bow's respective ends, for attaching the bowstring * Nock (arrow), in an arrow, the notch in the fletched (feathered) end of the arrow, for engaging the bowstring People *H ...

is a small notched piece that is attached to the rear end of the shaft, for engaging and receiving the propulsive push from the string during shooting. Nocks are made of either plastic or aluminum.

Size and weight

There is not any hard and fast rule of bolt sizing. Generally, the bolts are 15 to 22 inches long but the standard length is 20 inches. Experts recommend longer bolts but they have certain disadvantages as well. The weight of the bolt can have a serious effect on the range of the bolt. The bolt's total weight includes the bolt's weight, nock, insert, vanes, and broadhead or field point. Almost all bolt manufacturers will list how many grains each shaft weighs or how many grains are in each inch of the shaft. A more massive bolt, e.g. at least 400 grains, will have better downrange energy and offer better penetration but will travel more slowly and thus drop more due to gravity during its flight. A lighter bolt will fly quicker and give the shooter a longer range, but might not have the desired penetration.

References

{{Authority control Archery Arrow types Projectiles Crossbows