It's my understanding that if a C&R licensee bought it, he can't sell it for money, he can "gift" it to another party. If I'm wrong about this, there are a boatload of C&R holders here that will set me and you both straight on the rules.
Who are THEY?you can make a profit on any particular gun that you sell, you just can't buy and sell enough so that it replaces your current income as your source of money, then they consider that a business, there is no law as to how many you sell or how much profit you can make as long as you are not in the business of trading in firearms without the proper ffl01 license