Hunting with an AR-15? Protecting your self from robberies with the most popular military assault weapon? Recreational use?
Maybe it's, again, the dumb "restriction on fully automatic mode" that managed to make that an acceptable reality, but people with bit of an experience with an AR15/M16/M4 would certainly tell you that the fully automatic mode is the "recreational" mode while the semi automatic is the one you use if you actually want to hit your targets. there is simply no actual use for the automatic mode since it is aimed at suppression, essentially, scaring your opponent to lower his head so he can't shoot back which is kinda redundant giving that every squad has SAW that far better serve that purpose. even, if not especially, in a club full of people, firing on semi automatic is far more deadly which is partially why that killer had such a high casualty rate. removing the full auto mode so it could be sold is just a cynical spin by the NRA.
The twisting feature of the AR15 barrel makes it a bad hunting-for-food rifle because it raises the chances the bullet will bounce inside the animal's body and leave poisonous led fragments, unless the hunter uses a led free ammunition which i bet is something most AR15 owners don't use. regardless, even if it can be used as a hunting rifle, so what? an FN MINIMI can also be used as a hunting weapons.
An AR15 is a bad weapon to serve as a defense against home intruders. its size makes it impossible to get into the cupboard's drawer near the bed so it's less likely to be easily accessible. its longer frame and heavier weight gives a slower twist arc, which is why in close quarters soldiers prefer other weapons. its only advantage is in its fire power, but any 9MM handgun would suffice at those ranges.
A Collectors item? i carried an M4 for 3 years, literally day and night and there's nothing i wanted more than to get it home with me and keep it for the sentimental values. but who gives a damn what i or others want? assault weapons should not be collectors items just like Claymore mines, mobile mortar launch pads and hand held rocket launchers shouldn't be. it might upset some people but that's very acceptable in my opinion.
I am not strictly against licensing hand guns for protection but allowing civilian people to buy military assault weapons for that purpose is taking it way too far.
Btw, If you want a good example for mass shootings getting contained have a look at the recent terror attack in Tel Aviv where after less than 5 minutes it was over because of the readily available armed guards who managed to contain two terrorists, which resulted in 4 kills, 1 of which wasn't even hit by a single bullet but died of a heart attack.