While NEF will warn against it, and most likely void your warranty, they know shooters will use surplus ammo with .310-.311 bullets. So I suspect they will simply follow their current practice, with most if not all chamberings, and ream the chamber throats out to create an excess freebore condition. A built-in swaging die so to speak. Probably not conducive to good accuracy but it results in a noticable reduction in chamber pressure.
Too bad they don't consider the potential sales volume (too low???) worthy of a "new" .310 or .311 bore diameter barrel run.
Guess its tough to fly like an Eagle when you think like a Turkey!