According to 325 WSM
and 300 WSM
(and other reloading pages), the 300 WSM equals or exceeds the velocity of the 325 WSM on 180gr BT's.
I just wrote Browning a letter saying I would be their first customer to purchase a 325 BAR (they now offer the 300 WSM BAR). I love my light kicking 338 WinMag BAR and was hoping to get another big mag auto. After reviewing the performance of the 8mm, I don't think I want one. Perhaps I'm just spoiled by my 300& 338 RUMs.
At 200FPS slower than my 300 RUM, how can it be called a Mag?