JBM ballistics worked well enough with CenterX and my kidd rifle that I was able to plug in the MV from the box and go and win 3 consecutive matches at Texas Precision Matches. This was a couple of years ago at this point, but I have been nothing but pleased with this free online ballistics software. To that point, a buddy at the match asked for my dope- he shoots a vudu- and he went and won that event. Neither of us so much as shot over a chrono. As far as I know, he is still using that dope for his 22lr matches. If you are having issues with JBM ballistics, it is probably you...
JBM has been nuts on for me. But you have to understand which inputs matter and which ones you can leave as a default.