re: #5 FormerDirtDart
A Facebook friend posted about this incident this morning. If the photo is the weapon in question it is an M116 (Originally designated M1A1) pack howitzer.
That weapon has a five mile range. So the only safe distance, in my opinion, would be five miles plus another mile.
That range owner certainly should have known this.
As far as being available there are far more powerful weapons that can be fired on ranges in America.