Unlikely to write a report without pressing charges. That would almost be considered a waste of the police officer's time. Do you know this neighbor's full name? If so, check him through Missouri's Case.net online to see if he has any criminal charges either in the past or pending. It may give you a better idea of who you are dealing with. I'm with RPS on this one. If you find out he has a felony, you may wish to contact the county prosecuting attorney to report a felon in possession of firearms. If that's the case, I would call the U.S. Attorney's office too. As for the berm, I would simply move it. You certainly have the right to move things that are on your property back to his. I know it's more work than you'd want to do, but it is likely the only way you can do it.
Also, you may want to look into taking him into small claims court for the property that has already been damaged. I don't know what the value is, but it would likely give you a small judgment against him and he would certainly get the hint at that point. If you take that route, you may wish to consider splitting the difference on any judgment awarded if he'll stop shooting or shoot in the other direction or something. That way, you won't come off as too heavy handed. Remember, the goal is simply to deter his behavior, not necessarily punish him, right?
While I also agree with JD regarding the trespass, and possible other violations of the law, remember where you live. In those small counties, it is sometimes difficult to get local law enforcement to take this type of behavior too serious. Especially when they do what you describe (run and hide, then come out when the law leaves). In the worst circumstances, situations like this can take quite a while to resolve.
Lastly, I suppose you could get all Hatfield/McCoy on him and just start your own target practice in his direction.