I am fairly certain section 18.2-308.8 will not hold up as constitutional under the
DC vs Heller decision. That decision is pretty clear that the 2A protects firearms "in common use." ARs and other semi-automatic weapons have been judicially determined to be "in common use", unlike weapons like machine guns. For this, see the 1994 Supreme Court Decision
Staples vs US https://www.law.cornell.edu/supct/html/92-1441.ZO.html. The recent Kavanaugh confirmation hearing, before it became a sh*t storm of pointless 30 year old events, was a reaffirmation of the "in common use" protection. I know that
Heller II never made it to the Supreme Court for a real ruling on 'assault rifles' but believe that if it does, it will go in favor of the weapon as constitutional.
Not to say that the legal channel is the best way of 'resolving' this - the voting box clearly is - just citing it as a protection.