I think in actuality the 7mm WSM offers nothing over the established 7mm Rem Mag. The 300 WSM is only popular because it came out first and was the latest and greatest, but it offers nothing over the 300 Win Mag. The 270 WSM offers better ballistics over the 270 Win, and costs less then the 270 Weatherby Mag so it is the only WSM that actually fills a niche.