I shoot them, here is list of ones I use or have tried.
404 Jeffrey- 400 gr tsx
2 Different- 375H&H- 300 GR TSX , 270 GR TSX(preferred loading) 2800fps with barnes max load, 235 gr TSX-3000fps with max load
375 ruger- 235 and 270 gr TSX
416 Rigby - 350 gr TSX - 2 Cape Buffalo with this combo, 2600 fps 3 grains below max listing. Figured that was enough speed and load was acccurate in my rifle.
2 Different 300 winmag's, 165, 168, and 180 tsx, and 180 gr ttsx loaded to 3000 fps and this load shoots cloverleafs when I do my part.
30-06 - 165 and 168 tsx.
Going to try some 225 TTSX in 338RUM when gunsmith gets it finished and delivered to me.
Have had good luck with them and they seem to shoot accurately in everything.
As far as the reputation for fouling, haven't had a problem. Just do regular cleaning routine.
Good luck with them in your 300rum, think you will like them.
Jeff