I have a question about what to do when you put in all the atmospherics into exbal and you put your velocity reading from the chrono of your load and the bc of the bullet from the manufacturer and the computer is off by a little bit from acual data. Im aware about standard pressure and what to put in for the atmospherics, thats not what im asking about here. Im asking because i know there is more than likely going to be some error from the chrono and also the bc can be different for many reasons. So if the atmospherics are all plugged in right, than the velocity and the bc are the veriables. so how do you go about finding the right bc and velocity to plug in for that load?