When it comes to gun rights and marijuana, the two haven't mixed from a public policy perspective. I remember when the issue first came up in Oregon, which was the first case I ever read about nationwide. Medical marijuana patients in Jackson County and Washington County in Oregon were denied concealed carry permits by the County Sheriffs. There were legal challenges, and the cases went back and forth. Ultimately the court cases were moot because the federal government came out with guidelines forbidding permits for people who consume marijuana. The guidelines have led to outcry from gun owners across the nation who happen to be marijuana consumers (usually medical marijuana consumers).
One state where there have been issues is Colorado. Activists are hoping to change that with an initiative. Per The Cannabist:
The "Colorado Campaign for Equal Gun Rights" is working to put a question on the November 2016 ballot to have Colorado ignore guidelines from the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives about firearms and pot.
The measure would change state law to prevent sheriffs from denying concealed carry permits because of marijuana use. It's a new frontier in the marijuana wars, and one that has divided gun-rights activists.
"It's just ridiculous," said Edgar Antillon, one of the campaign organizers, who argues that firearms aren't kept from alcohol drinkers. "Somebody can get extremely drunk --- Saturday, Sunday, Monday, and all week if they want --- and they can still get a concealed carry permit."
It would be interesting to see if a federal challenge to the initiative, assuming it succeeded, would overturn it. After all, it's mainly federal policy that has prevented concealed carry permits to be issued to marijuana consumers. This is absolutely a situation worth monitoring.