What do I do about gun shots ?

Bullets are a clear threat to your safety. You have an action for damages for trespass and nuisance and even statutory damage to property. You definitely need legal counsel. If you are in the Southeast Michigan area, I could represent you or, otherwise I can try and find a good real estate attorney for you. Collect any bullets that have hit your propery, they are evidence. Call the police too, advise that gunfire is hitting your home. Send a letter to the other landowner and advise them to cease and desist immediately.