Ft. Chaffee Range controls phone # is 479-484-2272, Arkansas Game and Fish is 479-478-1043. I spoke with both offices and this is the deal. To hunt on Ft. Chaffee you must attend an orientation. The cost is 20.00 and the next class will be in March. The AG&F regulates the hunting. You must check to make sure that the area you want to hunt in is open, Chaffee has several areas. You can hunt hogs after orientation, in an open area with any weapon that is suitable for an open season game animal. IE .22 during squrill, bow during deer archery etc.
Hope this helps