I use the 185gr TSX in my 338-378 wthby. Accuracy is outstanding, velocity is a nominal 3450fps. I use this rifle/load as a long range deer rifle and have taken one whitetail at appoximately 325 yds...
I would be willing to bet you will achieve good results, with the TSX in a 338win, if that what you are reloading. The TSX seem to make the process of finding a good load relatively easy, at least thats been my experience with six different chamberings..