Distant Shots adds 40% of Weapon specific Base Damage for enemies that are “far” away
You can get an idea of the effective distance from this video:
(I don’t know if the distance it triggers is fixed, or whether it’s relative to the size of the room)
About the numbers:
- This calculation (load the page and click simulate) shows that the Weapon specific Base Damage is 1,565, of which 40% is 626
- This is the calculation including the applicable bonuses (GunHeart works like a Small Attack Up, i.e. 0.5 Big Attack Up) shows that the Ground Melee damage is 4,002 - the actual value in game is 4,001
- 4,001 + 626 = 4,627 is the damage when Distant Shots are active