Others will have more intimate knowledge of the details, but public ranges of different types will often be associated with municipalities or counties. Some areas have a strong city organization and weak county, while other counties are well funded and in a better place for ranges outside OR inside city limits. You’ll find some cities get along well with counties, while others are at each others’ necks. There will be a care taker and they need to be paid somehow, even if all they do is open and close a gate, and sit in the maintenance building. Anything completely free and open to people expected to self govern their behavior will be a mess on many levels.
We tried to do a free public range at a college and it very much depended on a champion in the athletic department that would support the idea and run it like a pool, weight room, or running track open to the public as well as students. There are different levels of risk management in colleges - intramural sports have the least liability, athletic areas open to the public have more liability, finally classes overseen by an instructor are expected to be the most secure and free of problems. Without buy in from the athletic department it wouldn’t have mattered if we had fund raising set up for all the required materials. They will only do something if there is significant interest, so getting signatures from potential users and testimonials from important stakeholders in the community goes a long way. Space, time, and staffing is limited so any new use of space will be at least a year away and needs to be budgeted as part of next year’s overall plan. I imagine it’s quite similar when working with counties and cities.
It’s a big project and you’ll learn a lot about working with organizations.
You might have an easier time making a club to fund space rental, volunteer staffing, and fund raising for equipment. It can be a partnership between the club and a city or county, or all 100% the club. Free sounds good, but a minimal fee goes a long way toward funding things that have to be purchased.
This is also a big project and you’ll learn a lot about running a club. If there are other sportsmen groups or athletic clubs in the community they are often a good source of knowledge and encouragement, because they know exactly what you’re going through. Often these come and go depending on how much time and effort the key leaders are willing to put into it.
Best of luck