My Brother's home went through that years ago. The bluing was crapped and the stocks got some surface char. He sanded, rechecked, and refinished the stocks, bought an entire Oxpho Blue hot bluing setup and redid the metal. The rifles outlived him, and my other Brother and our kids still shoot them.
Fire can be destructive, but a lot of that destruction can be simply cosmetic. This is only one anecdotal example, and caution should be your first consideration. By all means, hot handloads should be permanently removed from those firearms' menus.
It was that example that turned me off on fire protective safes. Too unwieldy, too expensive, and too small inside to justify that expense.'
My preference is for a "fire-room". A decent sized closet, with multiple layers of drywall (don't forget the floor and ceiling), with steel gun cabinets inside for access protection, makes a better approach IMHO. I have often heard that those pricey gun safes have drywall inside their shells as their primary means of heat-proofing, anyway.
Greg