Im dialing in a few guns for long range shooting. I have a CED crony. Im taking my vel, and putting it into JBM. Im using thier BC for the bullets. All the temps, bar, Hum, and alt are correct. When I get out too 700 to 800 yrds and beyond, the charts are off by a little bit. .5 MOA at the most. Im wondering what others do to tune thier charts. Do you adjust your bullet speed or the BC of the bullet. Thanks.