If you aren't a handloader I would say go with the WSM. If you do handload the WM will achieve more velocity than is capable of the WSM case. I'm a believer that the WSM needs a barrel of 24" and the WM benefits from a 26" tube. So be careful when choosing a rifle such as the Browning A Bolt it's offered with a 23" barrel in the WSM and the WM comes with a 26" tube. In the Winchester line the WSM comes with a 24" and the WM with a 26". If you're looking to Savage they provide both with 24" tubes. There are many others but I would say these are the most populare American made rifles. I left out Ruger because looking throuht their catalog it appears they only put 22" barrels on their WSM rifles. Also, of note if you are looking for a light easy to carry rifle the A-Bolt is the way to go and you will have to live with the velocity loss of the 23" barrel. I do believe both rounds are capable of taking all but the largest bears on the NA continent. For most people you won't be able to tell the difference in the two. Best of luck on whichever you decide to buy!!!!!