You are pretty close to being correct. For some reason the media has forced the public into believing that all firearms need to be registered. This is way off base. While there are certain licenses and permissions granted for an owner, many laws are also left to the state an owner resides in. There is no direct federal law commanding gun registration. If there were, this country would plunge into civil war.
As far as an "assault rifle," this again is a media fallacy. Tank, I believe, had an AR-15. He did not posess a military weapon. It certainly is not an automatic "machine gun" (It has one bullet per trigger pull). In fact, the AR-15 is an excellent target weapon. For many it is the rifle of choice for long range shooting competitions. It also happens to be a varmint gun. You are completely incorrect that it has no use as a hunting gun. Did you know that the AR-15 is only a .22 caliber? It is not even legal to hunt deer with it in all 50 states, however there are plenty more animals that are legal to hunt than deer.
I guess I do not understand why it is a big deal if someone has an "assault weapon" if it is owned legally. Assault weapons are certainly not illegal and there are many sportsman uses.