Assault rifle is the term; assault weapons is a term invented by anti-gunners to slop negative emotions from machine guns over onto lots of other semi-automatic firearms. If you use the term assault weapons, you are playing into the anti-gunners' hands by letting them define the argument.
Regarding assault rifles, they were highly regulated before they were even invented. The anti-machine gun regulations date from the 1930's; the first assault rifle, the Sturmghewer, was invented by the Germans in 1944 or so. Mikhail Kalashnikov created his in 1947 after deciding it would be good for his country to have one. And, Eugene Stoner invented the AR/M16 in the mid-1950's or so.
If anybody gives you an opening, just look amused, and off-handedly twist the argument back by redefining the argument without saying you are doing so and say, "Oh, assault rifles were illegal before they were even invented."
QFT
You see how insidious the anti's are with their serial misinformation and media assaults (pun intended)? Right here, just in this one thread, were several "gun people" who didn't know what an "assault weapon" is versus an "assault rifle." ASSAULT WEAPON is a made-up term. It's not a real "word." It's a lie with just the tiniest grain of truth (all good lies are like that) deliberately made up to SCARE IGNORANT PEOPLE because "assault weapon" SOUND LIKE "assault rifle." "Assault rifle" has a very specific and immutable definition. If a thing does NOT fit that definition, it is NOT an assault rifle. A Browning M-2 50-cal is NOT an assault rifle. An M-62 Vulcan is NOT an assault rifle. An SKS is NOT an assault rifle. It should also be noted that "assault rifles" are, by definition, NOT HIGH-POWERED!
However, being a completely ******** made-up term, the definition of "assault weapon" can be easily modified at will to demonize whatever it is you're trying to scare people about. There is NO fixed definition of "assault weapon." The current usage seem to be any semi-auto firearm with some kind of "scary" attachment (pistol grip, flash hider, "grenade launcher" [groan], etc). My new Ruger 10/22 was not an "assault weapon" when I brought it home, but it is now because I put a scary-looking black plastic stock with a pistol grip on it. The fact that it is mechanically the same firearm is completely irrelevant when all one is trying to do is scare people who don't know any better. Recently the anti's have been trying to call semiauto handguns "assault weapons" as well, especially with normal capacities of more than 10 rounds.
Us "gun people" should avoid the phrase "assault weapon" like the bad cliche it is. AR-15's, AK-47 knockovs, etc, are NOT "assault" anythings. They are simply semiautomatic rifles.