I think just about every single city or town has an ordinance on the books prohibiting discharging a firearm inside city limits, and you would likely have to seek special permission from your town council to do so in the privacy of your own (safely constructed) home range. They will likely crawl up your butt investigating whether your facility will produce noise pollution or lead pollution or contribute to delinquency of minors and whatever else they can come up with to mess with you just because they can.
However, if like me you live in the county outside of any municipality, you may have far fewer such problems. There are a couple gunsmiths around here who have bullet traps for test firing in their garages and such, and as far as I am aware, nobody has snitched on them or complained. That's mostly because folks out here in rural areas tend to not get freaked out by such activity. Also, neighbors tend to be far enough away from each other that muffled gunfire inside a nearby structure usually aren't loud enough to be disturbing to anyone in the first place. However, if you live this far out,...then you aren't really that far away to travel just a short distance to some open land to shoot at,...so why go to all the expense of building some subterranean boom tunnel?
Yes, indoor ranges exist inside city limits. But I would venture a guess that if you talked to them (and they answered truthfully) you would learn how much horrible BS they go through just to keep their permits and what it took to get them. I'm also certain the cities require them to carry very expensive insurance.
And speaking of insurance,...how would your home insurance policy react to an active shooting range on the property they are contracted to insure under the previous provisions? I hope it doesn't flood or anything, since I think it would likely be determined to be outside the scope of the policy. They'd probably cancel your policy the moment they discovered you had such a thing. Companies are cancelling policies right now for discovering in satellite imagery properties that have trees they think are too big and too much of a liability.
I think this is one of those "don't ask, don't tell" subjects. If you dig a small range, make sure it is only ever identified as a fallout shelter or similar living space. Never admit it's true purpose. This would also explain all the ventilation you would need to outfit it with.
Back in the 80's before Shooter's World opened down around Indian School Rd. and 27th Ave., right there just a stone's throw away was also Wells Fargo Armored Car Service, just south of the tire shop that sits on the corner now. Back then, I worked for them for a brief period, and they had there on the property a "mobile range". It consisted of a converted 53 foot trailer from an 18-wheeler. The interior was lined with 6x6 posts from floor to ceiling on either side, as well as on the floor and ceiling, to prevent the mid-range .38spl wadcutters from penetrating out the sides. And the backstop was just about 4 feet deep of stacked sandbags, fronted by more 6x6 posts. The only weapons ever discharged in there were the aforementioned .38 revolvers. There was zero ventilation, by the way. (Cough, choke.) It was inside this cramped little shooting gallery that guards working for Wells Fargo would fire 36 rounds for their qualification score. Somewhere in my desk I still have my little blue business card sized Q-card with a perfect score of 360 points. A maximum of 3 shooters standing beside each other could use the trailer at one time, along with the rangemaster, of course. But let me tell you,...3 guys firing 36 rounds of greasy smokey cast lead reloads inside an enclosed trailer CANNOT be healthy. (That's 108 rounds for you numerically challenged.) I have no idea how much airborne lead I ingested that morning, but I could taste it all day. But then Shooter's World opened, and the "mobile range" disappeared. Was the thing ever licensed by the city of Phoenix? Probably not. I'm sure the city left them alone if they wanted money in the city to be picked up in a secure manner. Something about not what you know, but who you know,...or similar. Who knows?
