ok im looking up how to correct for wind in the army's sniper hand book i found their formula that they use to correct for wind under that is the chart that they use to do the same thing so my problem is that the formula that they have does not match up with the chart that they use...so why is that and which one should i use the formula or the chart?....keep in mind that i would like to just use the formula cause i dont want to carry the chart around.......the army hand book that i use is U.S. army sniper training (FM 23-10)