even within a 50 mile radius?
Are you kidding? Do you know how much gas costs? There are other things I could volunteer in without the gas expense and get similar satisfaction. Public departments in my area are very restricted on volunteer use due to union contract restrictions.
Being a reserve officer in an already established department isn't going to get this job done. No city is going to pick up the liability. Buy a farm with a few people who are interested for various reasons, incorporate, get the certification(Sinclair Community College is local and cheap for OPOTA which is less hours than most states).
Not worht all the trouble for the full autos alone, but if anyone who completes the certification can have full autos to play with, even if under some relatively light restrictions, such as having to sign them out, then I think it would sweeten the pot a bit.
In my state private citizens can own NFA items.