A couple o thoughts from old JohnyMac...
All automatic fire has less accuracy unless the weapon mounted on a tripod or other supporting accessory. Automatic fire has it's purpose coming out of a primary however in my opinion it is if you are being over ridden by the enemy.
Anybody with just a passing interest in machinery and a schematic can alter any semi-auto weapon to fire full auto. Heck you could just make a "lightening link" and drop it into your AR.
Last on this subject, unless you have a M16 bolt carrier group in your AR (Legal to use in semi-auto rifles) a bump stock, lightening link, or three stage trigger, your rifle is going to jam.
And yes pkveazey, the ignorance concerning any firearm from Flint-lock to 249 SAW, is astounding. What is even crazier is "they" don't try to learn.