By "exercising an ability" I think you mean, "exploiting a loophole". Applying for a federal license to buy and sell guns when you have have absolutely no intention whatsoever to buy and sell guns (merely to obtain them for yourself at a discounted price) is dishonest.
Call up some manufacturer, tell them you're a retailer and you want to order some items at wholesale. That OK? Is that honest?
Never mind. You probably think it is. That'll teach me try try to argue morality with someone who doesn't have a clue. Hey don't worry -- if it's legal that means you can do it. Screw everyone else. Look out for #1.
WHO IS THE "EVERYONE ELSE" WHO ARE GETTING SCREWED IN THIS SCENARIO?!?!?!?