I like the idea of a vault door also. You can fabricate a reinforced block "room" to the size you need, very easy if you already have two masonry walls in place to use. Should be on a basement slab for best results. I bought the Top Of The Line Browning door several years ago (less than $2,000 delivered) and built around it. I would never go back. Mine will hold lots more guns than I have at the moment, along with much ammo, and in outstanding safety. .