Basically, you cannot be a medical marijuana patient, or a legal recreational user and a gun owner due to federal law. It seems the belief that marijuana makes you a crazed, addicted killer is still en vogue. The ATF has restated this in the past so people don't forget.
The federal prohibition vs. state legalization will simply continue to prop up the black market and do nothing to end the war on drugs. It'd be nice if this country woke up in this regard, one of these days.
Massachusetts Native (Tough to be a gun owner!)
Owner of: S&W Model 10-5, Beretta 92fs and a Mossberg Maverick 88 "Security" Shotgun