A locked metal box is just that, and with a torch or a cutoff saw it takes exactly the same (brief) amount of time to break into a big badass safe as a smaller one.
The very vast majority of gun safes are locked metal boxes. I directed my stipulation to them and with that exact description.Perhaps if your talking about a locked metal box. But safes come in all sorts of varieties. Some of my safes, bring what you want, you're not getting into them in a brief amount of time.