Cartridge shoulder geometry

[jmikell870]

Any one know why most modern cartridge shoulders are angled with flat shoulders to achieve a bottle neck, as opposed to having rounded or spherical geometry?
The web of a cartridge is pretty spherical. I'm sure this is to increase strength at the base of the cartridge where strength is critical.
But, I'm not sure the of effect from having radius cuts to achieve a bottle neck. Thoughts?

 

[ShtrRdy]

I don't know the answer to your question but I'll point out that Wetherby cartridges have a radius transitions to the shoulder.

 

[918v]

It’s more expensive to make reamers with rounded shoulders.

 

[Steel head]

Weatherby has rounded corners.

I’ve also seen a cartridge with a convex shoulder.

It would be interesting to some studies on those designs.