Hate to break it to you fellas, but if you fill out a form 4473, there is a question: are you a lawful or unlawful user of marijuana either medically or recreationally. If you are honest and check "yes" your firearms purchase will be denied federally. Federal law still trumps state law, and it's the same law anywhere a 4473 is required to purchase a firearm.
However, yesterday I passed a 4473 and the ffl knows me well, knows i smoke all day, and knows i grow. If he wanted to be a dick he could deny the sale himself and report it to ATF. Only thing i love more than weed is guns, and I've looked at loopholes in laws that shouldnt exist in the first place. If you answer the questions on that form honestly, yes, both of you have lost your rights, lying on a 4473 is illegal as well, but innocent until proven guilty.