I used to sell gun safes in my gun shop a few years ago. The safes that we sold are constructed in total using 1/4" plate. We had a customer that had a break in, his safe had a 1/4" door with gage material for the top and sides. The perps busted the sides and top of the safe with a pick-ax. Between guns, girlfriends jewelery and camera equipment he lost around $34,000. The safe company replaced the safe for free, which he sold and then bought one of ours. The safes that we sold are Drake Safes built locally here in Roxboro, Carolina. Greg Drake builds a first class safe and if you want to talk with him you can call him at 336-597-5059 I'm sure he'll be glad to talk to you. I have one of his safes in my home right now and probably have somewhere around 70-75 k worth of guns and jewelry inside. Keep in mind to keep your tax records in it and you can write it off on your taxes.
Just my experience! Sniper270