Just because the AR-15 doesn’t have a bolt carrier group doesn’t mean the guy holding it doesn’t have one.
Oh that will work. I can just see it, "Uhh, could you wait a sec Mr. gun confiscation guy so I can break down my AR-15, insert the bolt carrier, load it and then shoot you"
Exactly.
I bet I could install the BCG, insert a mag and chamber a round in less than 5 seconds.