Some of the recommended 30-06 loads specify a longer than normal COAL. That gives just a bit more case capacity.
But the short answer is, I don't think SAAMI maximum loads for the 270 are ideal. If you check the reloading data, most stop respectfully short of the 65K max. Since the propellant gas can't read the headstamp, loading 30-06 to 65 KPSI is as safe as loading the 270 to that level.
I have pressure measuring equipment, and generally run my 30-06 at about 58 KPSI.
I personally have seen two early Remington 740's both in .270, heavily damaged...SUPPOSEDLY with factory ammo. One looked pretty good except for being locked up tight and one had a gap betwixt barrel and action face and a splintered wood forearm. Neither shooter admitted to handloads. The one that we were able to open eventually...the Federal brass was parted but did not look that bad, leading us to believe the rifle failed..with just a cursory inspection. I don't know what the final outcome was with Remington. Neither shooter was injured.
