Gun Control & RKBA

The original AR-15 was a select-fire rifle in .223 caliber, based on the AR-10 design (7.62x51). It was sold to the military, by Colt, as the M-16. The models that were available on the civilian market were semi-auto only versions, beginning in 1963. It was originally marketed as a sporting rifle, NOT a poor man's battle rifle. As a matter of fact, there is a blurb at the following link about what they did to prevent converting the original semi-auto version to full-auto.
http://www.gunsmagazine.com/1964issues/G1264.pdf

The modern AR-15 is quite different from the original M-16, due in large part to extensive modifications to prevent easily converting them to full-auto. Yes, it can be done, but it is neither easy, nor is it legal for the average Joe, unless they have the correct paperwork in place. And since the number of crimes committed with full-auto !R-15's is on the order of infinitesimal, it's a safe bet to assume that there's no stampede of gun nuts making their AR-15's in to "weapons of war."

There is one definition of an assault rifle. Just because American politicians have co-opted the phrase and twisted its meaning into something else, doesn't make it correct.
http://www.tulprpc.org/attachments/File/Army_Gives_Definition_Of_Assault_Rifle.pdf

And the phrase "assault weapon" is mainly an invention of the gun control groups.
http://civilliberty.about.com/od/guncontrol/a/Assault-Weapons.htm

The Gun Control Act of 1968 specifically addressed private sales, exempting them from any background check requirement. This is NOT a loophole.

https://en.wikipedia.org/wiki/Gun_Control_Act_of_1968

Anyone who tries to identify it as such either doesn't understand what a loophole is,
http://www.merriam-webster.com/dictionary/loophole
or is deliberately distorting facts in an attempt to make them fit their narrative.

Anything else you wish to use your pretzel logic on?

NOTE: Modern AR-15 semi-auto rifles are NOT in use in any military that I have ever heard of. However, I can't state that as an indisputable fact. If you know of one, please provide some documentation.

Edited to add a link to a story about the Associated Press Stylebook definition of Assault Rifle (fully automatic), and Assault weapon (semi-automatic only):

https://www.washingtonpost.com/news/the-fix/wp/2013/01/17/is-it-fair-to-call-them-assault-weapons/

Edited again to soften the tone and remove what could be construed as a personal attack.