What bullet weight did you use? Light and soft cup and core bullets that tend to fragment upon impact at magnum speeds and fail to penetrate to the vitals causing a superficial wound that in some cases fails to kill the animal quickly and they can run long ways and not be found.
I have used the SST with great results just need to use the right bullet weight for the cartridge, for example.
On my 7mm-08 I use the 139gr SST pushed at just over 2,800 fps and at this speed most shot from 50 yds to 300 yds are DRT's with lungs turned to jello and above 300 to 600 yds they take a few steps and down they go, these are double lung shots avoiding the shoulder and I mostly get exit holes. The occasions I hit the shoulder the bullet still reached the vitals and did it's job.
Now on my 7mm Rem Mag I can't use the 139gr, it will fragment on impact at magnum velocities at shots under 200 yds, the bullet is too soft for high velocities. Now the heavier 162gr SST is perfect for the 7mm Rem Mag even at 50 yd shots, it will penetrate and exit even if it goes through bone. The heavier for caliber bullets are tougher and hold together better.
Now if you want to push a light bullet fast then use a bonded bullet like the Interbond, Accubond, Scirocco etc, these will hold together and penetrate to the vitals.