I've noticed a peculiar phenomenon with 300 mags over the years. Most of the ones I've shot, if they liked a 165, they'd also like a 200, but not a 180.

I'd try a 180 and if it didn't care for it, I knew I had a 165/200 rifle.

Can't explain why...but I've noticed it too many times to ignore it. May or may otherwise apply with your Wby. Best of luck!

You only live once, but...if you do it right, once is enough.