For anyone that says "It's not an assault rifle!" - the AR platform comes off the shelf chambered for two different types of MILITARY ammunition. It is a weapon specifically meant to fire human-killing rounds. This is not an opinion; it is a statement of fact.
So to answer the question posed by the OP's post: the AR-15 mutilates the human body, as it was designed to do.
There is nothing particularly deadly about the .223 round that isn't common to all rifle rounds, particularly larger calibers. Rifle rounds are deadly to living creatures, human or not.
The military has, time and again, dropped and adopted rounds balancing many interests, not only effectiveness on the battlefield, but also the logistics of moving ammunition from point a to point b. Sometimes the latter comes at the cost to the former. Recall that when the 5.56/223 round was introduced, it was panned as being completely inadequate for human targets. It was replacing a .30 round that had more stability in flight, more range, and more punch when it got there. Those rounds replaced a .45 caliber round before that.
The reason people say, "not an assault rifle," is because in the gun world that has a particular technical definition that the AR-15 does not meet. Using the term outside of its technical definition is nakedly an appeal to emotion for political purposes. There are more sober ways to make the gun ban argument without resorting to this language, but I'm not holding my breath. Fearmongering is effective.
Isn’t that the hardest to get a hold of these days? I figure the entire western supply is being stockpiled by militaries and/or being sent to Ukraine. Or unavailable due to sanctions (not sure how much was manufactured in Russia and making its way to North America).
Though I’d argue military ammunition is moreso built to pierce through armour that most civilian’s bodies and personal vehicles won’t have.
.223 one of the more common AR-15 rounds is cheap and most options have free or reduced shipping[1]. You can get 1000 rounds shipped to your door for ~$400.
Per comments - brain-fart. Militarize into full auto. I don't hunt, sorry, merely worked with hunters back in the early 80's.
I think you mean “militarize into an automatic”.
B) "militarize a [gun] into a semi-automatic" - yeah, that's not a thing.
C) "No need to hunt with a semi-auto" - no, there are several subjective reasons one might prefer to use a semi-auto hunting, and several objective circumstances where it makes sense. Remember that semi-auto means one pull of the trigger = one round fired.