Damage from bullets modified by next parametrs:
- Headshot damage multiplier.
- Distance damage drop modifier.
- Frequency of dealing damage.
- Operator armor.

Headshot damage applies, if bullet pierces operator head. If it also hit body, only headshot will be applied.

Headshot damage multipliers:
DMR - x2
LMG - x1.75
ARs - x1.5
SMG - x1.25
Pistol&Shotguns - x1 (same as body)

Distance drop:
Distance damage drop different for weapons classes and scopes they have, so they won't be listed here. Just know, that further the less damage.
Damage starts dropping by some part of the total distance and stops on the other part, reaching minimal damage point

Frequency:
Hitting anyone with any semi-auto weapon turns on invincibility for few frames, making your next 1 shot in weapon do no damage.

Operator armor:
Each 1 armor point blocks 10% of damage.

So for 3 armor operator headshot damage from AR will be counted as:
baseDamage * distanceDamageModifier * 1.5 * (1 - 0.3)