It appears that Fort Polk, LA hosts a MWR (Morale, Welfare, and Recreation) range for its soldiers. The website says that it's open to the public. It hosts archery, shotgun, pistol, and centerfire ranges with berms out to 500 yards. The website says:
Hunters and marksmen not assigned to Fort Polk are welcome to use the Wildlife Management area and Recreational Shooting Complex if they follow a few basic guidelines. These rules are designed to make access to available leisure activities more convenient, while assuring the safety of the post population and its visitors.The Shooting Complex is open on Wednesdays - Fridays from 11:00 a.m. to 5:00 p.m. and on Saturday and Sunday from 10:00 a.m. to 5:00 p.m. The Shooting Complex can be reached by telephone at 337-531-6591 or 337-531-5350.
In accordance with JRTC and Fort Polk Regulation 190-3, unloaded firearms must be separated from ammunition and will not be easily accessible to the driver or occupants. The weapon must be in the trunk of a car, in a truck tool box, camper, or bed. The ammunition must be in a separate location.
I'm going to have to look more closely into this range. I've been wanting to try my hand at shooting past 100 yards.