Not to be confused with Recoil.
Accuracy describes a weapon's ability to land shots close to where it's aimed, and how close to its reticle will multiple shots land over a given period of time. While some weapons—including full-automatic weapons—are capable of landing shots directly onto the center of their aiming reticle upon their first shot, a weapon's accuracy value determines the chance of these shots spreading away from the reticle: the lower the accuracy, the higher the chance of the shot straying off the reticle. Consequently, accuracy determines the weapon's shot deviation over multiple shots in a given period of time: a high accuracy weapon will see multiple successive shots land close to one another, while a low accuracy weapon will see the same shots spread out further apart in different directions.
The highest possible accuracy value attainable in-game is 100, with lower values denoting reduced accuracy.
Effects on Performance
A weapon's accuracy value generally becomes important the higher its rate of fire becomes, as the weapon's successive shot grouping worsens the faster it fires. For example, while the Vulkar has a lower listed accuracy value (13.3) to the Grakata (28.6), the Vulkar can consistently land each one of its shots at longer range due to its low firing speed, while the Grakata's high fire rate makes its shots spray out at longer ranges. However, a Grakata is capable of landing shots as precisely as the Vulkar if slowly fired one shot at a time. In general, a weapon's listed accuracy value is more important for weapon groups with high fire rates, like assault rifles and machine pistols, while less important for slow-firing weapons like bows or sniper rifles.
Accuracy also affects multishot characteristics. The lower the weapon's accuracy, the more likely each projectile will be off-center. Equipping mods that decrease accuracy can make weapons with low projectile velocity, like the Torid, very difficult to use at distance.
Certain weapons like the Flux Rifle possess perfect accuracy (an accuracy value of 100) where all of their shots land directly on the reticle regardless of range or fire rate, while other weapons like the Ignis disregard accuracy as a mechanic due to their unique firing characteristics, capable of hitting enemies regardless of how they're aimed.
Accuracy cannot be normally improved, although three mods exist that can increase accuracy, often with a requirement to do so. These include Guided Ordnance for primary weapons (besides bows/snipers), Narrow Barrel for shotguns, and Targeting Subsystem for pistols, all of which require the player to hit an enemy and the accuracy bonus will only apply when aiming, for a limited time. Tainted Shell also exists for shotguns as the only mod that increases accuracy with no prerequisite to do so, nor a time limit.
Spread
The term spread is used to describe how "wide" the blast of a shotgun can be. Spread is not fundamentally different from accuracy, however. As above, bullets fired from single-round weapons will angle away from the direct center of the reticle, and the accuracy value of a weapon reflects how wide that angle can be. As one rapidly fires more bullets from that weapon, assuming imperfect accuracy, the bullets take random paths from the muzzle within a cone centered around the reticle.
Shotguns, as well as any guns with multishot mods, can fire one of their pellets directly centered, with all other pellets taking random trajectories from the muzzle within the spread cone. Reducing accuracy increases the width of the cone, and decreasing spread decreases the width of the cone. Accuracy and spread are inverse descriptions of the same underlying mechanic.
Accuracy Mods
Shotguns are often intentionally exploited for their wide spread to reduce the need to aim with precision or to strike more targets simultaneously. As a result, players frequently find it desirable to increase the spread of their shotguns with Vicious Spread.
Accuracy and Recoil
Unlike spread, recoil is wholly a separate mechanic, but it can also alter how accurately the player can shoot, as it nudges the weapon's reticle with each shot. As such, a weapon with high accuracy but high recoil may still be difficult to shoot accurately at high rates of fire (the Cestra being one such example). To distinguish the two, accuracy is about how far from the reticle the weapon might shoot its projectile, but recoil is the amount the reticle moves after the weapon is fired.
Enemy Accuracy
An AimGraph for pistol units, X-axes being the range and Y-axes being the hit probability.
An AimGraph for sniper units, X-axes being the range and Y-axes being the hit probability.
Enemies determine their total accuracy with an “AimGraph”. The graph explicitly maps the target range and hit probability to determine their accuracies. Each enemy weapon is assigned into different AimGraphs, with each weapons type possessing different AimGraphs depending on their role. For example, enemies aiming with a pistol are far more accurate up close, and the hit chance drops off as the target range increases. On the other hand, units with a sniper rifle are far less accurate up close, but get more accurate at medium and long ranges before dropping off slowly. Additionally, when enemies are made aware of the players, they will need some time to maximize their aim.
