300wsm is the most popular wsm!! Factory ammo availability shouldn't pose any problems the amount of factory loadsbeing put out for the 270wsm and 300wsm continues to grow and imo neither are going anywhere. Further evidence is the amount of rifles being produced by different manufcaturer's offering these 2 WSM chamberings. I am seeing 300wsm shells in the small town gas stations up here!! Suggests demand or the 300wsm gaining serious popularity. Yes price paid for such will be higher but small amount considering the investment we pay to the sport each year. I certainly wouldn't let that be the deceiding factor to which to buy.