IMO, the air quality issue and lead issue are two of the biggest factors. Be aware there will most likely be lead splatter which can contaminate the building walls, ceiling, floor, structure, etc. Then there is the lead dust and unburned powder issue. There could be EPA problems on the land now. IMO, I would not do anything on land I did not own and land which has not had a recent environmental study for any contamination (land and water - surface and ground).
I have spent many hours on gun ranges. How are you going to protect the building from a misplaced shot? If the bullet leaves the range, where will it go? Go to any indoor gun range and look at the steel plates on the ceiling and walls. If these plates are painted, you can tell where a bullet has hit them. Also note the condition of the floor downrange. Even outdoor ranges are installing steel above and to the sides of the outdoor range.
An indoor archery range may be something with less risk.