Per 18 U.S. Code § 922 (D)(3) and (G)(3) it is illegal to sell or buy a firearm to/as someone who is "an unlawful user of or addicted to any controlled substance." This includes cannabis, even though it is legal in a number of states, due to the fact that it remains federally illegal. I have been told this offense was considered a "violent" crime, but was unable to find a source for that, or any details about what federal crimes are considered "violent." A number of states classify crimes that most people wouldn't consider violent as violent, and it seems like there is far more of a rationale for illegally possessing a firearm being considered a "violent" crime than some offenses that are considered violent. Is possessing a firearm in a manner that violates federal law, particularly if one is violating federal law by using drugs while possessing firearms, considered a violent crime?
Bonus points if you can direct me to a list of federal crimes that details their classifications as violent or non-violent.
Bonus question: What is the definition of "unlawful user of or addicted to any controlled substance?" Particularly considering timeline. If someone used a controlled substance 30 days ago, are they an "unlawful user" still? What about 90? The only answer I could find to this is a BJS report which states: "Those using an illicit drug in the past 30 days -- persons that the NIDA defines as current drug users..."