Selling 3D models of objects based on real world things. Legal Question

redcap

If a gun, say the desert eagle, is copyrighted; how do artists make 3d models of them and sell them online? Serious question, I want to implement some guns and the like into a game but don't know what I can or can't use. Also if I want to resell my assets I don't know what I can or can not resell. 

Eric Chadwick

Do a search, has been asked many times.
http://polycount.com/search?Search=selling+real+legal