Here is my suggestion for a gun safe. It is based upon the premise that have kept magicians working for hundreds of years. It's all about illusion.
Go find a clapped out vertical freezer. Gut it and make the inside into a gun cabinet. Leave the light socket and jumper the door switch or just rewire the socket so it is always on and put a 15 w bulb or reptile heater inside to drive out moisture.
Most freezers I've seen have a key lock. You can use that if you want. Or, if no key lock, put a hasp and padlock on the door.
Now, make a list of stuff that would be in a freezer with dates. You know, corn, beets, chicken, rhubarb, etc., and even cross some off. Use a few different pencils and pens so it looks like the list has been going on for a while. Now tape the list to the front of the door. Crumple it up and maybe make it a bit dirty so it looks like it's been there a long time. Then for the icing on the cake, put another big sign on the door that says "NO ICE CREAM IN HERE!".
The crooks will walk right past that freezer and never give it a second thought.
This idea came to me years ago. A friend of my Dad's was a barber and his shop got burglarized a number of times. If he could not get to the bank with the day's receipts, he would toss them on a stool in the shop and throw a towel over them. More than once they tore his place apart and never noticed the deposit bag under the towel. Hiding things in plain sight fools'em every time.
If you are buying a safe for fire protection, read the specs and you may change your mind. There is a video of a safe that was in a major house fire and they cut it open to see how things inside did. Lots of rust and such and some melted plastic and burned wood. If if were me and I had a pristine High Wall, I'd insure it and keep it in the freezer.