When I lived in Arizona I could shoot in the desert without fear of hitting anyone by shooting into the side of a hill I used to shoot at alot farther ranges than I do now. There was a place just outside of the north side of Phoenix where people used to abandon old messed up cars, washers and dryers, empty propane tanks, camper shells and other old junk that they didn't want.
Several times we shot from 700 to 800 yards with scoped FAL's and H&K 91's and were able to hit the target without much trouble once we fired a couple rounds and walked the rounds in. That's about the farthest I've shot and actually hit anything. The few times we did it we shot at an old beat up dryer and a shot up VW bug that had both been there forever.
Mostly now I'm stuck shooting at a range where the farthest distance is 100 yards, except for when I get a chance to shoot on a deer lease or something and then I try to get in as much practice at 200 and 300 yards as I can.