Re: 500 yd range in MS, AL or west TN?
Pascagoula DCM range goes to 1k and while not "public" has a dirt cheap membership at $100 per year. You have to qualify to use the long range side by shooting a 600yd match or checking out with a certified coach.
It is set up as a standard NRA square range with a large berm and target carriers at 600, and another small berm at 1k. Once qualified, you can use the long range side whenever you like but you must provide an RO with comms to run the short range line to ensure safety. It means you cant go shoot by yourself past 200.
Its a pretty nice place. I still shoot matches there when I can get away from work.
Pascagoula DCM has a website and a forum you can check out with all the details and rules, etc.
Sean