Plan to build garage shelving using only 2x4s. Lightweight and inexpensive, yet durable and functional.
Some notes about the project:
You can make your shelving as long or as short as you like.
The gap between the legs can be increased. Mine are about 5’appart and they are quite strong. I would go wider (6 feet) so you can fit three of these giant vaults on tespershelf. A six-foot long shelf made from 42×4 boards can carry about 200 pounds, according to Sagulator.
You can get taller if you want.
You can add more shelves at any height.
Be sure to attach to the wall to prevent the room from tipping over or stacking.