Then type something up on a piece of paper, sign it and hand it to him. That has about as much credibility with the counter man as something printed in a book. Remember "His job is to move merchandise." In most cases Joe the counter man will tell the potential customer what they want to hear to make the sale. Hand him any of the popular references to show he was incorrect and expect a reply similar to, "That is out dated material. This is the one you really need". (Who hasn't heard that at a gun show table before?) Now you're back to square one because, "His job is to move merchandise." Educate the buyer not the seller.