I am sure long range air gunners can help me with this. I used a number of different ballistic calculators and found that nearly all of them for the same ammo and conditions give different data, confused which one to trust. And after printing few tables I did some test shooting and result I got do not match with any BC, very confusing.

Do you guys use BC for drop calculations or finding out hold over / under by shooting at different distances and making your own tables?