RL-26 is considerably slower-burning than H4831 and RL-22, which work great with 180-200 grain bullets in the .30-06 but are a little slow-burning for optimum results with 165's. RL-26 might work with 200's, but I doubt you can get enough in the case for 165's, and maybe even 180's.
MRP is basically RL-22 in a different can.
