I just started using my exbal program the other day,and I am having problems coming up with a velocity/b.c. combo that works for various ranges.I am shooting a 300wm with a 240gr smk.According to sierra,the b.c. is .711,and according to my chronograph,I am shooting 2480fps.I am sure my chronogragh is reading low,so I started playing with the velocity numbers and I can't get things to add up.I am zeroed at 200yds.,at 300 yards I dropped 8''.I then shot 492 yds,and was hitting pretty much center with 33 clicks elevation(1/4 moa).Then I had to elevate to 90 clicks at 810 yds.Based on the info. I have,is there any way I can get this mystery figured out?