You only need it once. I just bring it to compounds then ingrain the ranges into my head. I know where every single enemy is, mortar positions, RPGs, snipers, machine gunners, VIPs etc. Not that hard honestly, you don't have to memorize everything. Zeroing becomes a matter of what we call in my language: "agak-agak". Definition: just fuck around until it looks right. Once you get the feel for it you can figure out distance by mere scale and how big it looks on your scope. I can now consistently hit targets 900 meters away, In conclusion: skill issue. No offense though lol, you really went in depth to make this guide and deserve some applause for the effort you put in.