hello guys...i'm sorry to ask an apparently ridicolous question (because it is), but ARMA3 make every effort to make obvious things...impossible!

to cut it short, i just wish to place a sniper and make him able to see and hit targets at ranges up to 1500m (with a 0.50 lynx rifle).
it wasn't working, so i documented myself, and finally i made this script to try solve the problem:
  ...and it actually works....when its 12:00 in a sunny DAY !
at night or in rain it simply dont shoot!

i'm getting mad about this thing that should already work in default ARMA3 without scripts!
hope you can help me, thanks!