Making a few normative claims that are wrongheaded and easily logically dispelled don't qualify in this regard. Biden saying that we shouldn't be able to carry more than eight rounds in a mag (correcting his wording) isn't a lie or misinformation -- it's just logically stupid.
That said, I'd dare anybody who hates the NRA to point to a lie that they've told or perpetuated. If you can, I'd be surprised if you could come up with more lies and misinformation put out by the pro-2A side than I can point to off the top of my head from the gun control lobby.
I don't know if Biden was lying when he said that a 9mm bullet will rip your lung out of your body, or if that's just misinformation; but, it's demonstrably false.
There are public documents from gun control groups talking about the value of the nebulous term "assault weapon" to gain footing for abridgements of the Second Amendment. Namely, there are a lot of people who know full damn well that "assault weapon" is an Orwellian, meaningless term that they're consciously repeating to confuse the public to support an agenda.
How many times a day does a gun control advocate say that these united States is the only nation that has to deal with mass shootings? That's false. We're not in the top ten. Anybody who repeats that talking point is either a liar or a perpetuator of the lie.
The term "weapon of war" is repeated several times a day by the gun lobby. It's another Orwellian, meaningless term that a lot of people know is bullshit. They know that they can gain support for banning "weapons of war" from civilian ownership; but, two seconds of thought shows that that means just about every weapon. Glocks are being issued to the military now. My 1911 was standard issue for about seven decades, and some members of the military still carry a version of it. My level-action rifle was never issued to troops; but, some purchased them for combat on their own because they felt like they had a better chance of coming out alive with a lever-action than with a mussel-loaded rifle.
It's a term mean to place us on a greased precipice, and they know it.
How about talk about "gun murderers?" Isn't that an interesting, sneaky term that people use? Yeah, Switzerland has more gun murderers than say, Russia; but, Russia has a murder rate ten times higher. Okay, well, it's because Switzerland has a robust gun culture; and, if they got rid of the guns, even those murders wouldn't happen, right? Well, I guess the gun control people forget that Mexico exists, and conveniently forgot to look up her gun laws.
How about their claims that the Second Amendment wasn't a protection of civilian possession of firearms, but a clarifying the right of a militia to have guns? If you can find a quote from a Founder or a Framer who said that his intent for supporting the Second Amendment was explicitly to ensure that a government controlled agency can have guns, and it wasn't for the people, I'll buy you a car (not really). That's incoherent. It takes two minutes to look up what Madison, Jefferson, Washington, ect. said in regard to the Second Amendment. It takes even less work to use logic.
If there's one prominent bit of misinformation that comes from my side, which I've been guilty of myself, it's that AR-15s are completely different from M-16s. They're actually pretty god-damned similar. They take similar ammunition. They're similarity powerful round for round. The main difference is the ability to shoot full auto or bursts; but, even soldiers seldom use their service rifles in full auto.
The difference is, I'm telling you the truth that I got something technically wrong. It doesn't shake my principles. If anything, my worldview is bolstered by the fact that we the people are allowed to have similar weapons to our government agents.
Bottom line, I'm right. The pro-2A side is right. We're right because we don't encounter moments when we feel compelled to lie, speak in unclear terms, or ejaculate hackneyed quips and talking-points. We get shit wrong; but, we don't get our facts wrong nearly as often as our opponents.