I have flu, no humor right now
Do 22LR AR-15s mods exist? yes but the normal caliber is the school shooter's choice. Misinformation of that kind is dangerous and I wonder if intentionally deceitful.
Expertise does matter, especially when dealing with such levels of confident and ignorant.
For example.. My friend's teenage son was shot in the head through the wall by his neighbor who was a moron. The boy would have been far better off had he been killed outright.
I advised Tsing Tao a while back after he said he used his own AR/FN for 'home defense' to put bullet proof drywall around his kid's bedrooms. This is because his FN SCAR 7.62 is VERY powerful and stray rounds would go through interior walls like they were not even there.
His response? he has "hollow points". He reckoned that they would fragment, a common myth. They actually go through drywall, like 20+ sheets + much soundproofing (in a video I posted) and still easily kill.
The point is that handing military grade (just not full auto) guns to ignorant men is breathtakingly foolish. I have no problem with Americans having ARs (I do if because of peer pressure), I am just saying that they need to properly trained (a couple of weeks with the national guard, ideally more in the spirit of "well regulated") as a crazy number of accidental incidents occur.
The Army don't give you a real gun until they think you are trained and appreciate what it is, but a civilian can pickup basically the same gun with nothing comparable to actual training?
The NRA are in the business of lobbying for the gun industry. Their gun safety courses are a pathetic joke. And some people are just too crap to own a gun, just like some can't pass a driving test.