Accuracy
The higher your accuracy, the higher your chance to hit a headshot, and lower chance of hitting legs.

Calculating Accuracy During Combat

Your operator can have an accuracy value of 0-48 and your weapon can multiple that accuracy up to 2x. So the max accuracy you can have during combat is 96.

How does accuracy work? (Example)

At 0 accuracy, you have a 33.33% chance to hit an enemy in the head, body, or legs.
Body Part
Chance of hitting
Head
33.33%
Body
33.33%
Legs
33.33%
Let us say your character has an accuracy of 5 and your sweet sniper multiples that by 2x. In combat, you'll have 10 Accuracy points. The chance of you hitting an enemy's legs decreases by 10%, and the chance of you hitting an enemy in the head and body increases by 5% respectively.
Body Part
Chance of Hitting
Head
38.33%
Body
38.33%
Legs
23.33%
Now, what happens once there is no longer a chance to hit an enemy in the leg? We begin to decrease the chance of hitting an enemy in the body and increase the chance of hitting the enemy in the head.
Let us assume our combat accuracy (Operator Accuracy * Weapon Accuracy Multiplier) is equal to 70. We start by deducting the 33% chance of hitting the enemy in the legs.
Body Part
Chance of Hitting
Head
49.83% (50%)
Body
49.83% (50%)
Legs
0%
After reducing the chance of hitting legs by 33, we are leftover with 37 accuracy points. We then subtract these from the chance of hitting the body and add them to the chance of hitting the head.
Body Part
Chance of Hitting
Head
87%
Body
13%
Legs
0%
As of now, there is no way to achieve a 100% headshot percentage. It may be reviewed in the future under special conditions

How does Accuracy Scale?

Accuracy skills with your operator as you level up. You get a big bonus during the early levels and then get some diminishing returns as you reach the max level.
Y= Accuracy, X=Operator Level