CountryBoy19
Grandmaster
It's called a vault door and almost every single manufacturer of safe's has a line of vault doors as well. They're made to go directly into concrete openings and bolt in place. They cost about the same amount as a similar safe does, but that's because 90% of the cost in a safe is in the door. I recommend you look at the big manufacturers like Ft. Knox, Sturdy, Liberty etc and check out their vault doors.I've got an old coal room off my basement that ive been wanting to convert into a walk in gunroom/safe. Its watertight but i need to find a safe door to install it. I would probably weld up some plate steel to box in and then weld the front to the safe door frame. Problem is getting the door and steel plates down the narrow stairs. About killed 3 of us getting an old cast iron wood burner out of there!
IMHO, the best bang for your buck on a truly secure vault door is going to be a Sturdy. If you have more questions after your online search, call Terry at Sturdy and he would be happy to answer them....