#1. Why used WR the standard length actions ? The answer is : To make it cheap !
#2. Is it possible to prepare the standard length action for the .318 cartridge without butchering the front receiver ring ? The answer , you guess it , yes . Several makers did so.
#3. Ask any c o m p e t e n t riflesmith to build you a mauser rifle after that WR pattern and listen what he can tell you.