Legal marijuana patients are unable to purchase and possess firearms. The legal issue preventing patients from legally using cannabis and obtaining or possessing a firearm is that marijuana is a Schedule I drug according to the Drug Enforcement Agency (DEA). States such as California, Pennsylvania, and Hawaii where marijuana is in the process of being legalized are debating whether or not they should be allowed their 2nd Amendment right to bear arms.
Realistically, the government is not worried about average, law abiding citizens consuming cannabis; they're more concerned with black market sales involving the use of firearms. However, from a citizen's view, it impedes on an individuals Second Amendment. We could say that the only solution is to reclassify Cannabis as a Schedule II drug. With Sessions as our Attorney General, will we ever get to that point? Lets see what unfolds in 2018. Fingers Crossed.