Why, oh why, couldn't they just base it on the 10.75x68 case??
Or, better yet, relaunch the 10.75x68 with these fancy bullets as THE do all cartridge.

One interesting note is the question of twist rates.
Mauser used exactly the same twist for the 10.75 and the 404 Jeffery even with a wide gap in bullet weights. Not as wide a variety as this 10.3 has, but I think there is a sweet spot in twist which will work for a wide variety of bullet weights.