Who get the AR15s?

Wrong question, it is who manages them. The private can have one, in military terms, but the master sergeant hands them out for practice and deployment.

So, if someone passes training, equivalent to a master sergeant in the army, then they are entrusted with ongoing possession of AR15s. That means gun club armories,  private deployment from secure offices, sometimes taking them home in secure gun locks. But it all implies training and connection to organized militia, be it private or public security; and implies a connection to the state.