That “gov’t gun “ thing brings up the question of how well controlled all that Homeland Security ammo and the guns that go with it are? In a Navy yard there would be rifles available at least to ship’s forces if not the Marine guard contingent. The rent-a-cops used for security on some bases wouldn’t have select fire rifles. Hope the shooter isn’t a sailor but the chance is there so far.
There are no ship at the Wash. Navy yard, and the only Marines w/ weapons close by are the gate guards 3 blocks away at Marine Barracks 8th and I. The Wash Navy yard is an administrative post; when I was there(stationed at the Barracks 93-95) DOD security did physical security, not the military.