The amount of upvotes is pretty hilarious considering you can't buy assault rifles anywhere. Shows how uneducated people truly are on the subject.
"Assault rifles" aren't available without special federal licensing and several hoops to jump through with ATF-- assuming you're trying to describe a rifle that's tactical in appearance and is "full auto".
An "AR-15" is Armalight Rifle, not assault rifle. They're actually a smaller caliber than pretty much every hunting rifle out there. While tactical in appearance, they're still 100% semi-auto, as are all firearms purchased by anyone in the US.
I'd also like to point out several places like Dick's Sporting Goods, Walmart, and a few others have reduced or completely eliminated carrying firearms all together, and might only carry ammunition (which you do need to be at least 18 to buy with ID or 21 in some instances). Other retailers have started adopting stricter rules on sales to reduce liabilities as well.
The issues with firearms has primarily been laxed storage by family/parents making easy access, lack of education in safety (where accidents often happen from mishandling), or the glorification in the media giving those seeking the attention their "15 minutes of fame"... (Personally, for the 'mass shooters' I feel its less to do with mental health issues like the media tries to claim it is, while realistically, I think a lot of it is desensitizing and glorification having made a name for themselves, however wrong/bad it is, and again, getting that spotlight).
I'll just add, both my son and daughter had firearms exposure in a safe and controlled environment and know how to handle them. The point is, if a friend ever says, "wanna see my dad's Gun?" They'll know how to handle the situation by understanding the dangers, walking away and telling an adult. If they're ever facing a school situation they'll better understand what one looks like and tell the nearest adult, etc.