If you are in an unincorporated area (sounds like you are), and are not shooting in a direction of people/structures (sounds pretty safe with 50 acres), you can shoot to your hearts content.
As far as building a range, I know of people who have done so, so it CAN be done. You'd need to check with your county zoning laws, and possibly even with EPA.
If you are just talking about renting a dozer and pushing up dirt for a burm, and setting up a small covered lean-to with a bench rest and such, I'd say no need to check with zoning. It would be a minimal structure (basically a shed).
I don't know Graham County zoning laws, nor am I an expert on the ins-and-outs of firing ranges, so take all I saw with a grain of salt (or black powder, if preferred).