I have used RL-22, Norma MRP, and IMR7828. Just look at the groups and velocities from each powder used with the 350gr TSX. Went out this morning to fire IMR7828 again so I could have a target and here are the results of all three powders in this order - RL-22, MRP, IMR7828.
RL-22 120grs 350gr TSX 2930fps .824"
MRP 116.8grs 350gr TSX 2891fps .724"
IMR7828 118.8grs 350gr TSX 2880fps .722"