Round Shoulders?

[Blakenzy]

Why do Weatherby centerfire rifle cartridges have rounded shoulders while most other rifle cartridges have angled shoulders? Probably a silly question but its something I have noticed and want to know if there is some specific reason behind this design.

 

[Gewehr98]

It was Roy Weatherby's marketing trick.

Weatherby literature places some emphasis on what's called "Venturified" brass, meaning the curved body/shoulder and shoulder/neck junctions would allow for better gas flow. (yeah, right, like the huge case capacity, higher working pressures, and generous freebore didn't do the trick!) Others consider the distinctive double radius to be a genuine Weatherby tool to force buyers to use Weatherby-exclusive brass, and for gunsmiths to use Weatherby-exclusive chambering reamers.