We’ve hit on this topic a number of times in recent years, but the news clearly isn’t getting out there. If you use marijuana, even in states where it is legal to purchase and use either medically or recreationally, you are barred by federal law from purchasing firearms.

The federal government is stepping up its efforts to keep guns out of the hands marijuana users, even as legal use of the drug is spreading around the country.

The Bureau of Alcohol, Tobacco, Firearms and Explosives long has prohibited gun and ammunition sales to unlawful users of marijuana, citing a risk of “irrational or unpredictable behavior.” Now, the federal agency has added a warning to Form 4473 making it clear to anyone applying for a permit to buy a gun that marijuana remains illegal under federal law and using it means you cannot buy a gun, despite laws in Maine and a growing number of other states that allow medical and recreational use of the drug.

The new language, added last week to forms filled out by gun buyers in Maine and nationwide, has raised concerns that the government is unfairly denying cannabis users their Second Amendment right to bear arms. And it has renewed calls from medical and recreational marijuana advocates for a change in federal law to catch up with the country’s changing views on marijuana.

Maine is a state with a deep tradition of gun ownership. More than half of Maine adults – 55 percent – surveyed in a Portland Press Herald poll of voters last October said they owned at least one gun.

Maine also is one of 28 states that allows medicinal use of pot, and tens of thousands of Mainers have received doctors’ certificates to use the drug. It is one of eight states plus the District of Columbia that have voted to legalize recreational use by adults 21 and older. Recreational use becomes legal in Maine on Monday.

However, the federal government classifies marijuana as a Schedule I drug, putting it in the same category as heroin, LSD and ecstasy. Marijuana users who lie on the form and deny cannabis use, whether for medicinal use or not, could face federal charges. Lying on a federal gun purchase form is a felony punishable by up to five years in prison.

Question 11e on Form 4473 – which asks if the buyer is “an unlawful user of, or addicted to, marijuana … or any other controlled substance?” – now has a warning printed below it in bold type that states: “The use or possession of marijuana remains unlawful under Federal law regardless of whether it has been legalized or decriminalized for medicinal or recreational purposes in the state where you reside.”