Weapon Spread (Fallout 3)



Weapons Spread determines the accuracy of a ranged weapon in degrees. Formulas here taken from the GECK wiki.

Spread Computation
$$\begin{align}\text{total spread} = \text{aim spread} + \text{weapon spread}\end{align}$$

The total spread is equal to a spread due to the character aiming, and a spread due to the weapon itself.

Aim Spread
$$\begin{align}\text{aim spread} = \text{perk effects } ( & \text{state effects} * \text{skill effect} + \text{limb condition effect} ) \end{align}$$

State Effects
State effects combine multiplicatively.


 * Crouching reduces spread by 40%. (multiplier: 0.6)
 * Using iron sights reduces spread by 65%. (multiplier: 0.35)

Skill Effect
The appropriate skill (Guns, Energy Weapons or Explosives) reduces spread by 0.5% (from 50% up to 100%) per skill point. (multiplier: from 0.5 to 0)

Limb Condition Effect
Damage to limbs increases (pre-perk) spread.


 * ArmPenalty is 0 with no crippled arms. 0.5 when right arm crippled with one handed weapon, 0.25 when one arm crippled with two-handed weapon, 0.5 when both arms crippled with two-handed weapon.

Weapon Spread
Weapon spread is equal to the Min Spread stat of the weapon in degrees. Weapon condition has no effect on spread.

Bugs

 * Prior to patch 1.4.0.525 ammunition that had spread modification effect (like 12ga), applied it to aim spread instead of weapon spread.