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 crossbows. The name "quarrel" is derived from the

French French (french: français(e), link=no) may refer to: * Something of, from, or related to France ** French language, which originated in France, and its various dialects and accents ** French people, a nation and ethnic group identified with Franc ...

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 Shaft may refer to: Rotating machine elements * Shaft (mechanical engineering), a rotating machine element used to transmit power * Line shaft, a power transmission system * Drive shaft, a shaft for transferring torque * Axle, a shaft around whi ...

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 or aluminium alloy (or sometimes both aluminum and carbon fibre are used), and is very lightweight for its strength. 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 Spine or spinal may refer to: Science Biology * Vertebral column, also known as the backbone * Dendritic spine, a small membranous protrusion from a neuron's dendrite * Thorns, spines, and prickles, needle-like structures in plants * Spine (zoolog ...

" 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 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 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 ca ...

(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 fins 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 ...

s, plastic or

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 A vertical stabilizer or tail fin is the static part of the vertical tail of an aircraft. The term is commonly applied to the assembly of both this fixed surface and one or more movable rudders hinged to it. Their role is to provide control, sta ...

(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 Drag or The Drag may refer to: Places * Drag, Norway, a village in Tysfjord municipality, Nordland, Norway * ''Drág'', the Hungarian name for Dragu Commune in Sălaj County, Romania * Drag (Austin, Texas), the portion of Guadalupe Street adj ...

-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 *He ...

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 String or strings may refer to: *String (structure), a long flexible structure made from threads twisted together, which is used to tie, bind, or hang other objects Arts, entertainment, and media Films * ''Strings'' (1991 film), a Canadian anim ...

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