Swop it for a few ounces. Im sure theres more than enough dealers near him who would be willing to sort a deal out... just remember to talk about it in person, most dealers dont like talking about things like that over the phone. Also, if your mate does decide to swop it for a few ounces, remember to ask the dealer in person, and dont bring it with you when you ask! He/she will most likely get pissed that you brought a firearm with you without their permission.
And make sure theres other people in the house aswell, even if its someone you trust - that way he wont turn the weapon on you and pop one in yo ass.