I have been looking into possibly going into business myself of opening up an indoor range, one that is not so politically correct and would allow assault rifles.
I found a few web sites that would be of some help.
First place to check and get info from is the NRA. They have a range source book that they sell that has all kinds of info in it.
web site address is:
www.nrahq.org click on shooting range services and there web site has a huge wealth of info. Plus the NRA holds each year a seminar specifically for Indoor and Outdoor range set ups. The seminar covers Indoor range ventilation systems,legal issues, and just a wealth of information and a number of people within the range community that one could talk to to be able to do networking with.
Another site I found that has alot of information on it is:
www.rangeinfo.orgThis site has also a huge wealth of information to draw from also.
Different manufactuers web sites that make targets,bullett trap systems:
www.actarg.comThis site is cool
www.caswellintl.comwww.copiusconsultants.comwww.shootingrangeproducts.comwww.snailtraps.comWell that should be enough to get you headed in the right direction. I would suggest looking at the NRA sight first, and ordering the range source books from the NRA. Then check out action targets, they got some cool target systems.
Hope this all helps.