I think Remington isn't offering the WSM because it's TOO LONG for the Remington short-action, by a CH...( I think this is correct)
Clever marketing by USRAC to make their new mags unfitting for the Remington Model 7 or the 700 short-action.
Remington's Model 7 is the shortest short action, though.
I bet they'll offer the 700 Police in .300 Remington ShortActionUltraMagnum.
How could they NOT?