Rifles Only is a pretty good course, but it really depends on what you are trying to achieve. Every Precision Course will cover marksmanship, scope theory, etc. but you need a good starting point. Start with the basics and wait on the cool guy stuff. Learn everything you can about minute of angle, mils, range estimation, wind and of course, marksmanship. Find a range where they have long range matches and attach yourself to some of the competitors who have been shooting a while. They will gladly mentor you (well, most of them). One of the best things you can do is get behind a spotting scope and watch a good shooter. You will learn more about wind, which is the hardest skill to master. Good Luck!