When I was in the Navy and serving on ships, the in-port quarterdeck was where all access to the ship occurred. When a visitor crossed the brow (gangplank, civilians call it), (s)he was confronted with at least one armed sailor whose job was to prevent intruders from gaining access to the ship. This sailor openly wore a pistol on a web belt, and during the hours he was on duty the gun remained belted around his waist. Remarkably, no accidental discharges occurred (/sarc). It would be quite easy to designate an NCO at each military recruiting office to be officially armed, prepared to deal with situations such as the shootings in Chattanooga. Such an NCO would hand the gun off to another NCO when going to lunch, and take it back upon return. At the end of the working day the gun could be locked in an on-premises safe, or taken home by the NCO in charge of it.