quote: two criteria–that the weapon is semi-automatic, and they have detachable magazines.

The AR15 was designed by EJ Stoner AS a military weapon. This was due to his patented gas mechanism which allowed faster firing (in addition to larger magazine capacity). The military adopted it and modifed it with a fully automotic firing option but it doesn't take full auto to be military weapon.

What should also be argued is ballistics. - the bullet is lightweight and can fly accurately for a long range- however that lightness of the bullet means once it hits a body it tumbles and causes a lot of internal damage.

If you google top hunting rifles you will NOT find it on a list because of the damage the bullet does. Nobody wants their deer meat all torn up.