I have been shooting a Winchester Model 70 Featherweight in 300WSM for about three years and have never had any feeding, or ejection/extraction problems at all. I also load for a friend that has the Tikka T3 in 300WSM and I highly recommend it. It's a great shooting rifle. I really liked the trigger on this gun. It's very light though. Plan on putting a good recoil pad on it if you're going to shoot it from the bench at all. We put a Limb Saver on his and it helped a bunch.
There is a site dedicated to owning and shooting any and all short mags. The address of the website is
www.shortmags.org and it has forums that cover reloading, factory loads, customizing, etc, etc. It's not near as extensive as Graybeards, but it has a lot of good info specific to shortmags.
Good luck and enjoy that new short mag.