One of my reloading manuals, though I'll have to check which one, states the same thing. I think RL-22 is made by Norma also. I have also read that RL-22 is the equivalent of the powder used in Swedish Prykskytte 6.5x55 military ammo, which would also lead me to believe that its the same as MRP. At any rate use published reloading info for RL-22 and not MRP for working up loads.