DHS

A federal department, the Department for Homeland Security endorses and recommends ARs with 30 round magazines for 'personal defense use in close quarters.'  That they are 'perfectly appropriate' in that role.

Good enough for them, good enough for me.  Thanks DHS!  Someone better tell the rest of the gov't.

They even recommend it be select fire.  Though if I was using a select fire weapon for self-defense I'd almost surely choose to use it semi-automatically, not automatically.