Even a Speer Grand Slam is a terrific bullet in the right circumstance. So is NP. But the right circumstance for those bullets excludes potentially close-range shots which start out at magnum velocities.
Swift, Norma, Woodleigh, and Barnes, likewise, are terrific bullets in the right circumstance. But the right circumstance for those bullets will mostly exclude shots from non-magnum cartridges where shooting distances might exceed 300 yards.
However, the metric changes a bit for hunting at high elevation.
A 308W, firing a 180 gr Speer GS at 2600, and an elevation of 10K feet (assuming elk, mountain mulie, etc), should reliably expand (and penetrate) all the way out to about 600 or 700 yards (not advocating shots like that, just looking at the physics).
Fired from a 308W with the same conditions as above, a 180 gr SAF, OTOH, probably won't provide much expansion past about 500 yards.
A TSX probably won't give much or any expansion past about 400 yards.
The latter two would be an excellent choice for a 300 WM at that altitude, but the Speer GS would probably be a poor choice for shots under 300 yards.
It really comes down to "what is the expected impact velocity?".