I love the idea of this chest, but can't help but think, how convenient for the burglars, all the guns in a nice box that two guys can carry off in one trip. A friend built a stand up version, several years ago, that was packed off by some riffraff, and then dumped in a ditch, when they found that muzzleloaders are hard to sell, and easy to identify.
His next project wasn't as pretty but worked better. He converted an old chest freeze into a gun chest. I helped him pull the compressor out of it, and pour the void full of re-enforced concrete. The lid is secured with a repurposed steering rack from a car, and a lug nut wheel lock that uses a special socket, this mechanism engages 7/8" rods that are incorporated into the steel framework that is welded into the lid. It ain't pretty, but when the same guys came back to get all the new stuff the insurance company had bought, they were caught spending too much time trying to get into the hillbilly gun safe.
Hungry Horse