I have looked at the V-line, Sentry, GunVault, etc. My two cents... Fort Knox is the best. I don't think you could open it with a sledge hammer. Remember it's only two cents. 10 guage body, 3/16" thick cover for a total of 24 lbs worth of safe. Take a look yourself.

Fort Knox: Americas Best Made Gun Safes, Hand Gun Safes, Fireproof Home Safes, and Vault Doors About US Hand Gun Boxes