What internal ballistics software does everyone use/recommend?
Are you referring to the EXTERNAL ballistic software? There is no internal ballistic software that I am aware of, since it varies from barrel to barrel and action to action. Short answer to your question is you can purchase one such as the Sierra Infinity 6 that I bought, or you can get it for free right off the net. Here is the website. http://www.eskimo.com/~jbm/ballistics/traj/traj.html I use it exlusively since it is very accurate for all of my calibers. Have fun.