Airsoft sniper windage, drop formula?

Ok, im an airsoft sniper. My gun if a welfire l96. I don't know anything about military snipers other than what ive seen on tv so i really have no info. I have a mil dot scope for my gun and was wondering if there is any kind of formula to measure windage or drop for airsoft guns? I tried modifying a real windage formula for airsoft, but quickly realized that wouldn't work...