Take all the advice and realy think it over. You won't make a lot of money as a small gunshop owner. It also takes a while to build a regular customer base and that's iffy still. Key thing is you don't make the $ on firearms but rather on accessories. Jujst lke gas stations...they make very little per gallon on gas but they hope you stop and buy itmes inside where the mark-up is higher. It's the accessories that make the profits.
Still, you're competing wth the large chain stores who buy in large quantities so they'll sometimes sell and what your cost will be. Now you need to sell a item other in the area don't offer. Good 'cause it'll be unique to your shop, but bad in that many won't posibly recodnize the items and pass them over.

After all this...it kinda goes back around to what briman said, if you gotta ask online about it, you proberly should look at a different route. Not being a wsieguy but having the desire to take the step really should inolve much more forethought than what a bunch ofanonomous pplonline will say.