Given similar performance in the new unbelted mags, which one will be more popular and will either become obsolete?

Quoted: Given similar performance in the new unbelted mags, which one will be more popular and will either become obsolete?

Both will become obsolete after the manufacturers decide they need something Bigger/Better/Faster to entice you to buy a new rifle.  If I had a gun to my head and had to pick one, I'd pick the WSM, but I think it's still an unknown quantity at this point.  I'll stick with my 300 WinMag for now, let somebody else jerk out the kinks.

shooter

USRAC's.300WSM vs. Remington's .300SAUM:  Ultimately, I think the 300WSM will be the most popular due to the numbers of rifles available - they simply beat Remington to the punch.  Also USRAC (Winchester & Browning's parent company) have offered the .300WSM in their full-size models (M70 and AboltII) while Remington introduced their 7mm and .300 SAUMs (Short action ultra mag - quite a mouth full) in the smaller and less popular Model Seven.  I also heard that Remington had some early pressure problems with their SAUM's trying to match or exceed USRAC's .300WSM ballistics.  However, USRAC will introduce a .270WSM (which is inherently accurate in independent tests) and should prove to be an awesome antelope round.  I don't think that either the .300WSM or .300 or 7mmSAUM will become obsolete in the near future.  Personally, I would prefer a 7mm SAM (SAM - short action magnum, which I think sounds better than WSM or SAUM anyway).  But a 7mmSAM just wasn't available at the time I purchased my rifle, and after talking with USRAC regarding the development of it, they were focused on the .270WSM at the time. The difference in recoil should make the 7mm SAM more pleasant to shoot.  As mine (.300 WSM AboltII) came from the factory it was downright evil to fire.  I've since remedied that problem by replacing the lightweight walnut stock with a heavier laminated thumbhole.  This stock, along with a barrel lapping and re-bed job MADE the rifle.  I'm getting <.750" groups with factory Winchester Supreme ammo in 150grBSTs and 180FSs.  As far a replacing the time trusted .300 Win Mag, well who knows, but I think that you'll see far more consumers purchasing SAM's rather than full-size belted magnums in the future.  After all, it all about marketing - you know the latest and greatest.  If you're in a dilema between USRAC and Remington, then I guess it comes to rifle preference, because the ballistics are so similar between the two.  At this time, there is a lot more reloading equip. for the .300WSM than the .300SAUM if that is one factor in your decision.