Firing sniper rifles

Unlike OFP, Sniper rifles in ArmA don't seem to have range adjustments. Amunition in ArmA has set balistic trajectory, so learn on what distance are each weapons sights leveled.

Optics/Ironsights leveling on distance: 
50m > MP5, pistols
100m > AK74UN, M4/M16 with Aimpoint, ACOG sights or suppressor
120m-400m > M4SPR
150m > Grenadelauncher ironsights  (M4 with ACOG 200m)
200m > SVD, KSVK, AK74PSO
300m > AK74, AK74GL, AK74U, M16A2, M16GL, M16A4, M16A4GL, all G36, machineguns
500m > M107

To hit soldiers closer than their default weapon sightings, scopes have notches above the centre cross hair.

For weapons sighted for 300 meters:

1 notch up: Distance = ?
2 notches up: Distance = ?

(A picture of the sights would be good here)