Well, your concerns are certainly well founded. Having fired several rifles of that "magnitude" and owning more than a few, they certainly are hard on a stock. Not to mention the shoulder behind that stock. If you were thinking about a laminated stock then your concerns would be a little less needed. But if you are going after a custom walnut then I personally would think quite seriously about adding another lug to "spread" that energy around so to speak. As far as your testing procedure, I would imagine 100 rounds should be plenty sufficient to show signs of stress. Granted anymore I surely wouldn't want to be the one doing the testing. My poor old shoulder just can't handle recoil like it used to. My .500NE will "straighten your hair" and it's getting to where I just can't handle full power heavy bullet loads from her anymore.