Look at what the Barnes manual says to start with the X Bullets!! They recommend to use the data for the regular X's with the TSX's!! I would imagine 57 grains of IMR 4350 would be quite hot, for ANY bullet!! Even though IMR and Hodgdon have the same numbers on a lot of powders, the powders ARE NOT interchangable. They each have slightly different burn caharacteristics. The best is to start at about 10% below listed max (rounded to the nearest grain) and work up in 1 grain incriments (thats what I do with the .30-06), until you have pressure signs, or you reach the accuracy that you want. Good luck with loading.