Ken,
Please reread my post, and also the post I was responding to. The original poster was inquiring about firearms storage, not ammunition storage.
I would advise anyone planning to use a locked room as their secure storage should do so only with great caution, consideration, and the advice of knowledgeable firearms counsel.
If one choses a locked room as secure storage, one must be confident the method used will satisfy the professional concerns of a law enforcement officer who happens to be in your home either with probable cause or under exigent circumstances.
Get it right and you are golden. Get it wrong you'll risk embarassment, criminal prosecution and many sleepless nights of anxiety, uncertainty and heartache.
If one has a fondness for a fortified, burglar alarmed, dead-bolted locked room for secure firearms storage, one could do that. Even inside of a properly secured locked room, I also recomend the use of an additional mechanical locking device designed to prevent unauthorized use of those stored firearms.
I prefer that my clients take a conservative approach to secure firearms storage, and, by doing so, deftly avoid inadvertently placing themselves on the wrong side of the law.
Darius Arbabi
www.massgunlaw.com