In RE 1.6, what variable makes damage reduce at a distance even if you hit a perfect shot?

[ghost]

And how does it work? I tried taper and the gun still did full damage at max range.

[qreeves]

taper set to values of 1 to 4 works across the lifetime of the projectile, and 5 to 6 works across distances. You are likely looking to set taper to 2 and taperout to 1.0 which will make the projectile taper out to nothing as it reaches the end of its lifetime.