I saw the weapon the shooter used and how many he had in his hotel room. The weapon known as an "assault" rifle was legal. Now the parts the killer used to "improve" the action of his assault rifles were a type of "slide" on the stock to make the gun bigger and easier to hold and manage and a type of canister that holds up to I think they said 250 rounds of ammo. Impressive was the only word I can think of while viewing these types of "canisters" but maybe "Oh, My God" was better. Next the assault rifle as it came purchased legally was compared to the assault weapon that was modified with the 2 items I mentioned that were simple, legal and could be bought easily on line. The first assault rifle shooting the target was a shot by shot deal. The new "make-over" shooting at the target was non-stop fire action. No doubt that the conversion of the assault rifle was into a machine gun. But machine guns are illegal. So you can buy the assault rifle and if you do the add on that is illegal to.