{{unreferenced, date=May 2008 Deflection shooting is a technique of

shooting Shooting is the act or process of discharging a projectile from a ranged weapon (such as a gun, bow, crossbow, slingshot, or blowpipe). Even the acts of launching flame, artillery, darts, harpoons, grenades, rockets, and guided missiles can ...

ahead of a moving target, also known as leading the target, so that the

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 ...

will "intercept" and collide with the target at a predicted point. This technique is only necessary when the target will have significantly displaced its position during the time the projectile would take to reach the target, which can become the case over very long distances (e.g. a long

sniper A sniper is a military/paramilitary marksman who engages targets from positions of concealment or at distances exceeding the target's detection capabilities. Snipers generally have specialized training and are equipped with high-precision r ...

shot), due to fast moving targets (e.g. aerial

dogfight A dogfight, or dog fight, is an aerial battle between fighter aircraft conducted at close range. Dogfighting first occurred in Mexico in 1913, shortly after the invention of the airplane. Until at least 1992, it was a component in every majo ...

against an opposing aircraft, or

anti-aircraft Anti-aircraft warfare, counter-air or air defence forces is the battlespace response to aerial warfare, defined by NATO as "all measures designed to nullify or reduce the effectiveness of hostile air action".AAP-6 It includes surface based, ...

fire against passing aircraft), or while using relatively slow projectiles (e.g. a bolt shot from a

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 ...

, or a

basketball Basketball is a team sport in which two teams, most commonly of five players each, opposing one another on a rectangular Basketball court, court, compete with the primary objective of #Shooting, shooting a basketball (ball), basketball (appr ...

thrown to a running teammate).

Gyro gunsight A gyro gunsight (G.G.S.) is a modification of the non-magnifying reflector sight in which target lead (the amount of aim-off in front of a moving target) and bullet drop are calculated automatically. The first examples were developed in Britain ...

s developed for aircraft of the

Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

displayed a

reticle A reticle, or reticule also known as a graticule, is a pattern of fine lines or markings built into the eyepiece of an optical device such as a telescopic sight, spotting scope, theodolite, optical microscope or the screen of an oscilloscope, ...

that compensated for target lead. Modern

fighter aircraft Fighter aircraft are fixed-wing military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air superiority of the battlespace. Domination of the airspace above a battlefield ...

have automated deflection sights, where a computer calculates lead and projects the solution onto a

head-up display A head-up display, or heads-up display, also known as a HUD (), is any transparent display that presents data without requiring users to look away from their usual viewpoints. The origin of the name stems from a pilot being able to view informa ...

(HUD). The visual assistance with targeting the gun is offset by the speed and agility of modern aircraft, compared to the days when targeting was less advanced. In

artillery Artillery is a class of heavy military ranged weapons that launch munitions far beyond the range and power of infantry firearms. Early artillery development focused on the ability to breach defensive walls and fortifications during siege ...

, deflection is also used against fixed targets to compensate for

windage Windage is a term used in aerodynamics, firearms ballistics, and automobiles. Usage Aerodynamics Windage is a force created on an object by friction when there is relative movement between air and the object. Windage loss is the reduction in e ...

and range. Due to the

Earth's rotation Earth's rotation or Earth's spin is the rotation of planet Earth around its own Rotation around a fixed axis, axis, as well as changes in the orientation (geometry), orientation of the rotation axis in space. Earth rotates eastward, in retrograd ...

, surface points have different velocities and curved motion, leading to apparent Coriolis drift of a long-range target.

Computer games

Modern computer games of the

first-person shooter First-person shooter (FPS) is a sub-genre of shooter video games centered on gun and other weapon-based combat in a first-person perspective, with the player experiencing the action through the eyes of the protagonist and controlling the pl ...

genre typically feature a number of relatively low-velocity projectile weapons such as unguided

shoulder-fired missile A shoulder-fired missile, shoulder-launched missile, man-portable rocket launcher, or man-portable missile is a rocket-propelled explosive projectile small enough to be carried by a single person and fired while held on one's shoulder. The wo ...

s, or fictional projectile weapons such as "plasma guns" or "nail guns", which necessitates an attacker to lead his aim ahead of moving targets. Computer games that accurately model the ballistic trajectories (including velocity) of firearms also require leading of fire, much as in real life. This applies equally to combat aircraft (or even combat spacecraft) simulators, where the velocity of the craft involved are significant enough to require leading with projectile weapons. Additionally, in older

multiplayer video game A multiplayer video game is a video game in which more than one person can play in the same game environment at the same time, either locally on the same computing system (couch co-op), on different computing systems via a local area network, or ...

s that calculate behavior on a remote server, even for high-velocity or

hitscan Hitscan in video game design, most commonly in first-person shooters, is a type of hit registration system that determines whether an object has been hit or not simply by scanning if the item used was aimed directly at its target and then applie ...

weapons, there are issues of latency that may require leading. Essentially, even if the shooter has the target exactly in their sights, by the time the information relating weapon fire from the shooter's computer has reached the

server Server may refer to: Computing *Server (computing), a computer program or a device that provides functionality for other programs or devices, called clients Role * Waiting staff, those who work at a restaurant or a bar attending customers and su ...

, the target may have moved enough to avoid the shot. However, modern game-engines use a

lag compensation In computers, lag is delay ( latency) between the action of the user (input) and the reaction of the server supporting the task, which has to be sent back to the client. The player's ability to tolerate lag depends on the type of game being pl ...

system which moves all players back to a point in time based on the shooter's

client interpolation Client(s) or The Client may refer to: * Client (business) * Client (computing), hardware or software that accesses a remote service on another computer * Customer or client, a recipient of goods or services in return for monetary or other valuab ...

time and

ping Ping may refer to: Arts and entertainment Fictional characters * Ping, a domesticated Chinese duck in the illustrated book '' The Story about Ping'', first published in 1933 * Ping, a minor character in ''Seinfeld'', an NBC sitcom * Ping, a c ...

(or, alternatively, by trusting the result calculated entirely on the client side) to evaluate if there was a hit or not. Such systems eliminate the need to lead hitscan weapons, but introduce the risk of players being hit by enemy fire shortly after taking cover behind objects, due to the latency causing a delay before the victim's computer receives the message that he has been shot.

Computer games

See also