The feds have some very strict specs for such vaults, thick steel reinforced Concrete walls, the floors are first on the list, along with a thick steel roof. It must have electronic alarms (When I was in boot camp in Guard Duty if we needed backup we were told just hit the wall of the Armory with a stone, it would set off the alarms and the MPS will arrive quickly).
Now, some Armories do not have those thick Steel reinforced walls. My old First Sargeent told us of his arguments with the feeds and his old Hunt Armory In Pittsburgh. instead of steel reinforced concrete walls, it had six feet of oak. The Feds wanted Concrete for that what they regs wanted, but the six feet of Oak was even stronger and harder to get into then steel AND he had the Engineering studies and reports to prove it. Every so often the feds would come back and wanted their concrete and every time he would have to bring out the studies and show them what they wanted was WEAKER then what existed. Hunt Armory was built AFTER the 1877 General Strike and the National Guard wanted a secure place for weapons. In the 1877 Strike, Pittsburgh was one of the center of the Strike. Do to fears that the Pittsburgh National Guard were NOT help put down the Strike, the other two Brigades of the Pennsylvania National Guard, Philadelphia and Harrisburg, were sent to Pittsburgh. It is clear from day one of the strike that the Pittsburgh Brigade of the Pennsylvania National Guard was suspect (i.e. they supported the strikers). In one Incident, the Philadelphia National Guard open fired on the Strikers but that was stopped due to fears the Pittsburgh National Guard on their flank was going to open fire AND NOT ON THE STRIKERS. That night it was decided to sent the Pittsburgh National Guard home, since they had no place to secure the weapons, the Pittsburgh Brigade was sent home with their weapons. That night the remaining units had one of the worse nights in combat history, constant fire from the strikers. Gun Stores were giving away guns to be fired on them. It is suspected that Pittsburgh Guardsmen remained and fired on the troops that remained. The Strikers even managed to get a Civil War Cannon off its war memorial and were loading it when the Guardsmen open fire on the men manning the cannon. That fire fight to keep men away from the cannon lasted all night. The next day the National Guard marched out of town with the strikers at their heels. Gating guns were used on the Strikers to keep them away. Pittsburgh was left to the strikers, and then all food and other shipments were denied into Pittsburgh till the City Fathers managed to convince people that they would be no food till the strike ended AND anyone leaving the town would be gunned down. Trains still ran THROUGH Pittsburgh, but with Gating guns before the engineers with order shoot anyone on the tracks and NOT to stop for anything.
I bring up the 1877 Strike for Hunt Armory was built afterward basically to store the guns of the Pittsburgh National Guard. The internal armories were designed to be bomb proof thus the massive oaks used. Such Armories have been the norm ever since, thick walls that are bomb proof but do to their size hard to miss.
Now, most a such armories are unmanned most of the time. The only time their are manned is when the Unit is being called into service (actual service or training), where their weapons may be needed. At such times the bolts of the various arms in the armories are returned to the armory. I pointed this out below, but the bolts of the firearms in such National Guard Armories are RARELY kept in the same armory as the weapons. Most of the time the bolts are kept in some local police station armory, an armory that is manned 24 hours a day seven days a week, The weapons without their bolts are useless, except as decorations. In theory you can order new bolts, but that would be a dead giveaway as to who stole the rifles. Since the Mid 1970s the bolts of M16s and semi-automatic AR-15s have been slightly different to make then technically non-interchangeable (Prior to the Mid 1970s the only difference was in the trigger mechanism between M16 and semi-automatic AR-15s but in the mid 1970s Colt changed the bolt to the civilian AR-15 from its Military AR-15, the later is called by the US Military the M16, the change was do to a previous robbery where it was reported all the thieves had to do was order AR-15 bolts).
Anyway, I suspect it was easy to find the Armory and being unmanned but locked, he managed to break the lock and steal the weapons, but without their bolts. Thus he had some fancy toys but nothing functional.
Bolts have been kept separate from weapons since the days of Bolt Action Rifles in National Guard Armories that are NOT manned 24/7 (and most are NOT). Thus anyone looking for a bolt for an AR-15 will be reported to the Government by anyone who even heard of this robbery. Being how quick they caught the theft I suspect it was a crime of opportunity, he thought he was going to get something he could sell, but ended up with nothing but a long prison sentence.
= new reply since forum marked as read
