After reading some of the above posts, there appears to be more than one way to learn how to shoot out to 500+ yards.
Option 1.
You can join the Marines, they will indeed teach you to shoot out to 500 yards. According to some here, that seem to have "been there, done that", they will seldom allow you to shoot out past 100meters, and almost never past 300 meters, and then only with special optics. They also will not give you the best tool for the job, being that they will only give you an M4 or M16, which are fine, but not known for their long shooting capabilities.
Option 2.
You can learn the way that I did. No 4 year commitment, you can choose your own rifle. No yelling, No bad hair cuts. You will be expected to be able to do your shooting with iron sights, however, if you choose to use optics, that will be allowed. I promise that they will not teach you anything that is copyrighted or patented by the US Military, all lessons are approved by the Founders of this Nation as appropriate for all age groups.
America is great, we always have quality options