I have a 325 WSM, and aside from being a very pretty rifle, I have little use for the caliber.
Case capacity is too small for the bore diameter. You get nowhere near 338 Win mag performance. I shoot all my loads over an Oehler Chronograph, and don't just spout useless advertised velocities.
Shooting 200 grain TSX bullets, regardless of powder I cannot exceed 2950 fps without excessive pressure 2900 fps seems to be a bit saner load. Same is true with Nosler and Sierra bullets.
If I drop down to 180 grain bullets, I can get close to 3100fps. Not bad velocities, but nothing exceptional.
My big problem is that I have a couple 300 Win mag rifles and even a 300WSM that will easily achieve the same 3100 fps with 180 grain bullets, which have a higher ballistic coefficient. The 325WSM is effectively equivalent to a 300 win mag or 300 WSM with 180 grain bullets. You get a little larger diameter with the 325 (frontal area) in exchange for sacrificing some ballistic coefficient. Not a good trade, in my opinion. And when you start to load heavier bullets, there isn't enough case capacity to get good velocities. And heavier bullets is the main reason to step up to the 8mm diameter.
So the 325 is just another esoteric 300 win mag, effectvely. Not bad company, but nothing special either. I am shooting my 300's and may occasionally use the 325WSM, but overall I haven't been very impressed and could have spent my money on a different caliber rather than "another" 300 wannabee.
BTW, case life has been reasonable, on par with 300 WSM. It is definitely harder to find 8mm components, and the available choices are far fewer than you would find in 30 caliber. My rifle is accurate, although not exceptional, but I don't see a long term future for this caliber.
Bill