I live in York County, near Hanover. I am not aware of any public ranges around, not even in the State Forests. You end up joining a "Sportsmen Club", most of which are very anti-black gun. There is a range up near Harrisburg (West Shore Sportsmen Association) that is VERY black gun friendly, and they have frequent handgun and rifle competitions. IPSC, IDPA, the NTI, a house-clearing range, etc. Only troubls is that it's a little over an hour to get there, so I tend to make a day of it.
The only other range I know of that's worth a crap is Jefferson Sportsmen, which I belong to. When I first joined up, back in '97, black guns were not common, and the "hunters" gave me a bit of a hassle, but I pushed right back. But now, we have tons of MD transplants moving in, and I see more black guns than ever before. Of course, this prompted the club to mandate a 5-rd maximum in the mag rule
But it's otherwise a nice facility, with 300-yard rifle, etc. I just do my general practice and longer-range rifle work there, and go to West Shore for combat related stuff (and to test fully-loaded mags for reliability).
I don't know anything about sherrifs signing Class-3 letters, but they didn't give any trouble in signing CCW permits, which I have heard that some sherrifs drag their feet and make excuses to drag things out. Not so in York County. I hear Adams is alright too (aside from their heinous taxes).
Also, make sure you check out the local townships very carefully, with regard to taxes, as their rates vary WIDELY. Adams County is more expensive to live in, due to their insane "Occupational Tax" - wherein you pay a tax based upon what your profession is. It can get quite pricey. Plus the Gettysburg liberals love to spend, spend, spend.