One thing to contemplate ... rather than a range open to the public, why not a shooting club? Dues, training classes (state required hunting, pistol and advanced), private lessons, special events, gun rentals, ammo sales, shooting supplies, targets, a nice snack bar where you can watch the shooters behind safety glass or on closed circuit monitors, and, or course, competition leagues.
Having a club versus a public enterprise would help support the place with dues, sales, and event fees. It also might help insurance cost if more serious shooters frequent the club versus the "public range" crowd who just go to blast the sides of the crater and make loud noises.
Just brainstorming out loud. I would think a more up-scale range would do well. There are many who don't go to Koko Head because it's outdoors, dirty, run down (although getting a face lift now), etc.