I'd imagine you'd make as much as any other hellish retail job - perhaps less since it seems nowadays many brick and mortar gun shops are sinking.
A lot I've seen just price themselves to death. People are informed consumers now, they know how much stuff costs online, and they're not going to be fooled in a lot of cases. If a store has a rifle for hundreds of dollars more than it can be had for online, even with shipping and transfer fee, a lot of people are going to leave it there to get dusty.
One of the most successful ones I know of, my favorite store, MOVES guns. They have some higher-priced collector pieces, and they also move Saigas out the door at $250 for the 5.56 and $260 for the 7.62. They get S&B ammo and sell it for cheaper than Wal-Mart. They get odd lots of milsurp and stack it all over, like treasures to find and grab, and price it low to move.
As I result, I spend lots of money at the place!
