Depends on what your smith has done with the feed rails because a std 700 short action would have to have the feed rails opened up to 7MM WSM
specs. The follower needs to be a short action magnum type to let the rounds move under the rails so make sure you have the right follower. The magazine for short mags is bellied out to let the rounds over also, and you should have put in a Wyatts extended box so you could leave the bullet out a little farther. If the feed rails were not opened up to wide by your smith the proper magazine box, and follwer should make it feed correctly.
It sounds like the rounds are not staying under the feed rails.
Elk Meadow Performance