Handling a different cartridge really isn't the issue though. The max pressure of the .30-06 is only about 5,000psi higher than the max for .223/556. Several smaller bullet diameter cartridges are higher pressure. .270Win, being rated at 65,000 psi and based on the .30-06 case is one example.
The problem is when something causes those rated pressure to be far exceeded. It's unlikely to happen in the circumstance that you dictate, but it's not a matter of "well it can handle this cartridge", it's a matter of "Well, it can handle 100,000psi" when something goes horrendously wrong.