Become a table top dealer and sell to your local community.
+1, and I suggest building your inventory with used guns and military surplus. People will pay higher-than-online prices for used guns and milsurp because they get to inspect the wares before purchasing. You won't have to sell at very low margins to stay competitive with places like Bud's.
Another advantage of going "tabletop" and is that transfers are exempt from sales tax in many states because they are considered to be a service rather than a taxable ware.