It occurs to me that ever year I go back to recurrent and fight a fire, right next to the fire range, could be the firing range where I requal with a required score. Shouldn't take too long, we are really talking about shooting at short distances here. Using the gun every year in recurrent would demonstrate its good working order. I believe that Cops requal once a year as well, though they do practice more frequently, as do I, as there is no point in having a gun around the house if you aren't current and qualified on it.
Locked door and a gun, or NO access at all to the cockpit. One or the other.
Cheers
Wino