WiFowler,
Whoever wrote that article is FOS in more than one way, but the biggie is the 7mm PRC has considerably more powder room than the 7mm SAUM, because its case body is the same diameter as the SAUM but almost .3" longer. (Also the 7mm PRC's shoulder angle is not "lower"--whatever that means--than the 7mm SAUM's, since they both have 30-degree shoulders.)
I am quite familiar with the 7mm SAUM, having handloaded for it for several years after it appeared, and took a bunch of big game with it from South Texas to northern Quebec. I never could get more than than around 2875 fps from 175-grain bullets with the best powders from my stainless/synthetic 700's 24-inch barrel, and the 7mm PRC is indeed capable of just about 3000 with the 180-grain Hornady ELDM--which has an extremely high BC.
