Zodiac was a sniper, but it was racially motivated, not random.
Charles Whitman was a sniper, but he shot from one location and did move methodically from one location to another.
Every once in a while I and my buddies will practice out to 400 yd with out iron sighted revolvers. We do very well with our Coleman can targets (7"x12") and I like to shoot silhouettes at Devil's Mountain at 300 and 400 yd. You would be suprised at what a lot of us can do with handgun. I use a gold bead front and V-notch rear to be able to hit coyotes at 100 yd.