CNN's Don Lemon is having a tough year, and it's not getting any easier. But he's great for cautionary tales. When, for instance, he tries to have a Ferguson-related conversation about guns and mucks it all up, he offers us a chance to learn something important and improve the national conversation.

In the clip above, from last night's telecast, Lemon cringeworthily fulfilled a textbook right-wing journalistic stereotype by completely misunderstanding what the term "automatic weapon" actually refers to. During a panel conversation with Van Jones and conservative pundit Ben Ferguson, Lemon asserted that just anyone can buy an automatic weapon. He's wrong, wrong wrong—but the way in which he's wrong illustrates a key part of the gun debate that's not being discussed well:

FERGUSON: The law says that you and I can't just randomly go out and buy an automatic weapon, so let's deal with the facts here. A semiautomatic weapon is gun that you and I are allowed to own, and in different places they have different rules. But to imply that anyone can walk out and buy an automatic weapon is just not true, Don.

LEMON: What do you mean anyone can't wa— Listen, during the theater shooting in Colorado, I was able to go and buy an automatic weapon, and I, you know, have maybe shot a gun, three, four times in my life. I don't even live in Colorado. I think most people can go out and buy an automatic weapon. I don't understand your argument there.

Ferguson, who is in the right on this discussion over the lingo, asks Lemon what the hell he thinks an "automatic weapon" is. The Blaze (sigh) picks it up from there:

"For me, an automatic weapon is anything that you can shoot off a number of rounds very quickly. I was able to buy an AR-15 in 20 minutes," Lemon said.

That's when Ferguson pounced.

"With all due respect, you don't know what you're talking about," the radio host shot back. "An automatic weapon is when you pull the trigger one time and it continually shoots off one after another, after another."

But Lemon refused to back down, claiming that he can do exactly that with the AR-15 that he purchased in Colorado and accusing Ferguson of "getting into semantics."

Well, yeah, it is semantics, but it matters. Journalism involves educating audiences with precise and accurate language. In this case, if Lemon had known what he was talking about, he could have challenged Ferguson on some important points.

First, the facts: There are "full-automatic" and "semi-automatic" firearms (as well as some other categories that don't really figure into this conversation). Fully automatic weapons continue to fire rounds of ammunition as long as the trigger is held down—machine guns, chiefly. These are highly regulated and extremely difficult to obtain, unless you're a licensed dealer or a rich collector. And even then, getting your Gatling gun on is not easy.

Far more common are semi-autos, guns that fire a single round with every pull of the trigger. These include most home-defense pistols and shotguns sold today, as well as the nasty-looking and easily obtainable assault-style weapons, like the AR-15, to which Lemon refers above.

Technically, all of these weapons are automatic firearms of one type or another, but most people in the know use the term "automatic" to refer exclusively to the rarer full-auto guns. Lemon and many other journalists aren't savvy to these subtleties. As a result, fairly or unfairly, they lose a lot of credibility in trying to address gun policy.

More importantly, their ignorance deprives them of an opportunity to address some real policy problems. In federal law, the distinction between full-auto and semi-auto is a somewhat antiquated one, and new technology is finding a lot of loopholes around it. Take a gander, for example, at this fancy rapid-fire thing:

Looks and sounds like a machine gun, huh? Except it isn't, and it's totally legal, as Mother Jones has reported:

Slide Fire is a company that sells gun stocks that you can use with an AK-47 or an AR-15. These attachments enable accurate "controlled rapid firing," according to the company's website, meaning "you can shoot one round, 2 rounds…15 rounds or a full magazine," as Jeremiah Cottle, the US Air Force vet who invented the product, told Guns America last year...

[D]espite enabling rapid fire that mimics a fully automatic weapon, Slide Fire doesn't appear to violate the production ban in the National Firearms Act. The law only regulates weapons that are designed to shoot "automatically more than one shot, without manual reloading." The way the Slide Fire works, as Cottle explained to Guns America, makes it easier for semi-automatic gun owners to do what they've been doing anyway: "bump firing," which is where you simulate automatic firing by rocking the gun against the trigger finger.

In essence, the Slide Fire—or even creative fingerplay—can make semi-automatic weapons shoot really, really fast, so they're not illegal. But they're super-popular: That single Slide Fire promotional video has nearly one and a half million views.

Yet because so few journalists even get how firearms work, they're at a loss to ask the right questions about problematic modifications such as these. It's like trying to get your grandma to identify cheat codes for Grand Theft Auto V.

Of course, this all may strike uninitiated unarmed citizens as irrelevant geek shit. Full-autos, or even rapid-fire cheats, aren't what's killing tens of thousands of Americans a year: semi-automatic pistols, shotguns, and assault weapons are. Acknowledging that fact—and not getting your butt handed to you in a distracting semantical debate—is a necessary step for anyone who wants to use public policy, however nominally, to address gun violence; not just to establish one's credibility, but to get at a deeper understanding of problems and possible solutions.

That doesn't mean that every critic of a wide-open, absolutist, NRA-style pro-gun ethos needs to be a proficient shooter or hunter. But on the other hand, if you want to have coherent opinions that are taken seriously, you shouldn't be a Don Lemon, either.