You can try it. If you just do airsoft you will go broke. I would find an owner and lease the building - at least 10,000 sq ft - 20,000 sq ft. You must add in paintball or laser tag to make it work. If you sell paint, it is a consumable, so that will help with income.
If you already own a building, you could make it, although just the taxes are going to be huge, even on a small building. Just taxes alone, on a $400,000 building are going to be likely $10,000 - $20,000 per year on the low end. That is $2,000 a month. Hydro and water will likely be close to $1,000 if you heat it. You need to do a serious cash flow statement to see what would happen. You would need a lot of cash to blow through at the beginning. You also need to always underestimate your numbers, because you will not likely get 100 people a month to start. You need massive dollars to advertise, because most of the cheap people on this board complain about anything over $30 for a field fee. Paintballers spend $100 a day all day for paintball. Go where the money is.
I looked at an old abandoned building in Toronto a few years ago for an indoor location. 25,000 sq ft. $5,000 a month. That is about the cheapest you will find. I would have made money there, but there are zoning issues and fire code issues that can shut you down. Good luck. There was an indoor paintball place for sale in Mississauga a couple years ago for around $400,000. It made about $500,000 a year and the owner probably took home around $60,000-$80,000. His lease was for $13,000 a month plus utilities and had about 15,000 sq ft if I remember. Minimum expenses probably around $20,000 per month.