ORIGINAL: cma3366a
DGH, what bigcountry is talking about is the aditional powder mass required by the belted mag. That additional mass creates greater (slightly) recoil for a given velocity. The WSM's do not use 'fast' powders, they use slow burning magnum powders just like the belted mags. How they maintainsimilar velocity comparedto the larger 'cubic inch' belted mags is through a pressure increase allowed by better case design, and stronger modern rifles.
Think of a .300winmag as a stock, naturally aspirated 454 chevy, and a .300WSM as a stroked 383 with a blower. A WSM is doing the samewith less volume through greater pressure within thatlimited volume.
CMA, don't bother, after his last statement, really not worth explaining. I actually have extensive experience with both, and I guarantee you my loads for both feel noticabley different.