I'd have to go along with Dogtown. If you're going to do the retail thing, a business plan is the first thing to nail down. push it, pull it apart and see where it fails and think it through again before you put in a penny.
I tried doing sales until even the big brick and mortar gun stores saw what Bud's was doing and made the internet market go crazy. They can get the guns people want (shown as allocated on the distributor sites) at a price that lets them charge almost as low as my dealer price and they throw in cheap or free shipping. plus, my customer pays no sales tax.
If i can get a popular gun, I have to pay for the distributor shipping and charge sales tax . By the time i add in cost to cover the shipping, the, 8.25% for sales tax and a few bucks for me, I was WAY over the price Buds, Grab a Gun, and KY Gun Co would charge. My business is also 99% transfers and about 1/2% of the remainder is doing USPS mailing for customers that sold their pistol on the internet. i save them tons by not having to use UPS or FedEx. The other 1/2% of my customers is me. I'm getting so many transfers that I'm able to buy the guns I want for my personal collection at a rate I never dreamed possible. There are some office expense and such, fees for my UPS store box and occasional trips to the FEDEX or UPS depot to pick up in-bound transfers,, but those are way down in the noise compared to the profit. the only other down side is having 3 guys sitting on my couch waiting for me to get a customer's paperwork done so they can get their gun next. The wife hates it until we go out to dinner on the evening's take.
Again, think it through, talk to a CPA and then think about it again.