Thanks for all the responses.
I have talked to a Norma rep. several years ago and he said basically what all you guys are saying. MRP and REL22 are virtually the same powder except the MRP is held to much tighter quality control standards.
I have tried both powders and I get better accuracy with the MRP. That's my bottom line and that's why I'll purchase the MRP over REL22, "If it becomes available again". I'll have to keep my eye on Black Hills I guess.
I receive quarterly flyers from Black Hills "Shooters Supply" a wholesaler in S. Dakota. They say they will have MRP coming either this spring or summer. I called last week and they don't have an arrival date as of yet.
About 3 yrs ago a really "hot" lot of RL22 got released. I loaded it for a big match without checking it. I was blowing primers and breaking trigger sears. went through three triggers in two days. Needless to say, I did not win.
Once I got home and checked the lot I had to come down 4.0 grains from previous lot. Last time I used RL22.
"Improved" does not necessarily mean better in industry terms. Industry whores out these terms to relate to a products availability, production standards, cost etc. Quality control and lot to lot variation ( the part reloaders are generally more concerned with) may or may not be a part of the equation.