It's a known risk, and there are guidelines to lessen or prevent lead exposure at the range, but I'd wager most shooters aren't aware.

For example:

Use jacketed or lead free bullets and primers.

Wash your face, arms and hands after using the range.

Change your clothes and shoes after using the range.

Wash your range clothes separately from your families.

Do not eat, drink, or smoke on the range.

Take the same precautions after cleaning your guns.

That being said, the folks at largest risk for this kind of exposure would be those who fire guns the most often, so that population would be the canary in the coal mine so to speak.

https://www.quora.com/How-often-do-police-officers-practice-at-ranges

"How often do police officers practice at ranges?

Most departments require re-qualification training once a year.

My department required shooting three times a year, once with our sidearm, once with our 12 gauge shotguns, and once with our AR 15 carbines.

As for my self, I go to the range 8 to 10 times a year. I am usually accompanied by 5 or 6 of my fellow officers. We are not for the fun, we are training by using the state required shooting plans and we add a little extra to it.

Most officers I know only go to range when required for re-qualification. Not because they don’t want to, shooting off a couple hundreds rounds is an expensive proposition."

Yeah... Might be a reason cops seem dumber than average, and they don't hire the brightest to begin with.

https://abcnews.go.com/US/court-oks-barring-high-iqs-cops/story?id=95836

Is it possible? Yes

Could it at least in part explain some behaviour? Yes.

But the missing question really is how much, and the answer is probably infitessimally small even if Real.

For lead exposure there are far easier and more common ways to get exposed such as lead pipes (which the US has a lot of).

But also you'd have to establish that the underlying problem is brain damage, and that is probably not true and instead reflects cultural bias.

There are many other reasons to explain American culture and behaviour which does not default to brain damage (or at least provable brain damage).

I would look at social and cultural issues first: an extremely weak political system, a poor quality general education system, high levels of religion, poor quality general health care, high levels of inequality including shocking levels of poverty.

The problem with the US is the extremes - if you have money you have the best the world can offer; if you don't then the state provision is shockingly poor. But alot of the crazies are also rich, and that comes down to the culture and society.

Lead poisoning is the least likely explanation, and is almost wishful thinking to try and explain things as a disease rather than normal human nature.

I think there's a much higher chance of slow-poisoning with heavy metals and other chemicals by food then shooting guns. Food quality standards in the US are poor. As well as nutrition wise. Malnutrition has a big effect on people their brain. The brain needs loads of stuff to function properly, not just corn syrup and fats. And with the poor US food safety regulations and poor tap water there's more poison then nutricions coming into your body.

I've been thinking long covid might also be a factor for it getting worse over the last few years.

Religion is the cause. You are not allowed to think outside the cult. There are a lot of idiot Americans who don't own guns or are exposed to them, so the lead theory is not valid in that sense.

It's really the idiocracy theory. Dumb people have more and more kids while smart people tend to have 0 to 2 kids. It's exponetially growing the amount of dumb people. Besides some people that had potential dumbed themselfs down by joining organized religion. very sad

The brain follows the same patterns as muscles: use it or lose it. The general population in America is very much not educated at all. So their brains lose the ability to think rapidly.

iirc most spectacular form of neurotoxic damage really only shows years later if lead exposure happened during childhood which also means that little effect will be seen immediately after cleaning up lead but will show up 20 years later or so. that's still leaded gasoline and maybe paint and water pipes to some degree