These days you need to know how to work on and troubleshoot modern military style rifles, especially the AR15 variants as every manufacturer except Ford and Chrysler has an AR in their lineup these days, and Chrysler may have one in a year or two! Reliabilty tuneups on popular SD handguns will also get you business. Refinish to include hot caustic blue, parkerizing, and the various spray on bake on "super finishes".
However, unless you are near a major city, most smaller towns in Indiana are not going to be able to support a gunsmith very well. I worked for one back in the 80s-90s, and he was never getting rich at it. Mainly it was a dribble of broken/malfunctioning guns of all types, maybe 1 or 2 a week, then the week before deer season every freakin' hunter for 3 counties around stopped in and wanted a scope mounted on their shotgun or muzzleloader, in a hurry for opening day of course. Three weeks later when we caught up, it went back to 1 or 2 guns a week. We also built custom muzzleloaders, "race guns" and made various semi autos from parts kits as well. This was in the back of a normal gunshop, which brought in more money than the gunsmithing. At one time we were the top Springfield Armory seller in Indiana! He closed up back when ATF was making renewals tough, trying to get the FFLs down from 225K to like 30K. It worked, he decided too much hassle for too little reward.
Follow your dream, just keep your feet on the ground and your options open before you commit 100%. Where you located at, I'm down here in Grant County, about dead smack in the middle between Ft. Wayne and Indy, right off I69.
