Here's a hint, kids: if you're going to go gun-shopping, do not do so while obviously stoned to the gills. In particular, do not ride around in the Magic Van inhaling the smoke from the herb of the fields (or just basking in it) and then go in to the boomstick shop reeking of ganja. You see, on the 4473 form, Section A, question 11.e., it asks "Are you an unlawful user of, or addicted to, marijuana or any depressant, stimulant, narcotic drug, or any other controlled substance?" followed at the end of the part you fill out by, "I certify that my answers to Section A are true, correct and complete...." over your signature.
It is quite literally a Federal crime to give false answers on that form. If the nice clerk at the gun store takes the form you have filled out, does the seller's sections and calls in to the NICS background check knowing you have said "No" to A.11.e. while sharing pot smoke strong enough to cause sneezing fits on the other side of the showroom, they would be complicit in a Federal crime. Generally, gun store employees are not interested in committing Federal crimes. They're probably going to ask you nicely to come back another time, when you are, ahem, perhaps more yourself?
This is not to say marijuana Prohibition -- or any other drug law -- is necessarily Good and Right. Personally, I think all those laws need to go; in my opinion, all they do is enrich and empower a criminal class while turning potential misdemeanants* into for-sure felons. It is, however, The Law, right there in ordinary typeset, and avoiding the breaking of it is trivially easy, what with the handy listing of prohibited and controlled substances.
In the Olden Days of, say, twenty years ago, the retail gun biz ran somewhat heavily to cigarette smokers. Tobacco has fallen out of fashion and indoor smoking bans (another stupid law -- I like the fresher air, but it's not my store and it doesn't belong to the City Council or State Legislature, either) have become the norm. The average salesperson at a gun store these days is a little younger, in a little better shape, and probably a non-smoker. They're going to notice the Eau d'Mary-Jane and, having noticed, can't pretend they haven't. And then they're going to have to Just Say No.
* Sorry kids, intoxicated is intoxicated and public overindulgence to the point of becoming a problem is not going to cease to be so just because the cause was Toledo Windowbox rather than Stoli. Too harsh? Too bad.
T. R. MCELROY'S STREAMLINED TELEGRAPH KEYS
8 months ago