Probably more appropriate for the Remington Forum than here on the Howa/Weatherby forum but.... in the past Remington's policy has been that any time they chamber a rifle for a round they offer the ammo for it. They have chambered some other Weatherby rounds in the past and each time offered ammo for them.
Now they are at least supposedly offering a limited edition rifle and one regular stock rifle (probably both this year ONLY) in .257 Whby. Mag so I'd expect that the ammo will be out by the time the rifles are. I've had one on order since I heard they were gonna offer them and so far none has shown up for me. I waited all last year on the limited edtion in .280 and never got it so doubt I'll get the limited edition .257 either.