Incorrect. The "AR" refers to Armalite, the original manufacturer. It never referred to "assault rifle", a practically useless term if there ever was one.

For whatever its worth, a caution from Bushmaster's catalog:

The position of the Bureau of Alcohol, Tobaco and Firearms (ATF) is that if your AR15 type rifle contains even

one M16 component, it is a Machine Gun. If you own an AR15 from any manufacturer, check to make sure there

are no M16 components in it’s assemblies. If there are, remove them immediately. Machine them to AR

configuration, or replace them and destroy the M16 components. Refer to the illustrations below to determine if

you have M16 components in your assemblies. If you have any questions about your parts, give us a call and

we’ll be glad to supply you with the legally acceptable parts.