I seem to remember reading somewhere -- perhaps here on accuratereloading -- that Alliant Reloader 22 is the same powder as Norma's MRP. Does anyone here know whether this claim is correct?

I've been under the impression that they are the same powder for several years. I can't remember my source, but it was one of the shooting rags.

Burning rates, faster to slower:

115. N-160
116. IMR-4831
117. AA-3100

118. WMR
119. H-4831
120. MRP

121. H-450
122. N-165
123. RL-22

124. H-5010
125. IMR-7828
126. AA-8700

According to the A Square reloading book (and my experience as well as personal knowledge) RL22 and Norma MRP are made on the same line in the same factory (Bofors Sweden).

There is about as much variation between MRP and RL22 as you find between lots of many powders. So, cut your load 10% and work up!

In case you are interested, the same source (A Square) says:

RL19 is N204

RL15 is N203

I have always been able to use the more-available RL data for the 3 above-mentioned Norma powder equivalents listed above. (I'm in Sweden: guess which powders are easy to get here?

Good luck.

jpb

I think that JPB has it about right. A factory will make it's powders in batches. Each batch is tested by closed bomb and other methods to detemine its energy and burning rate. If it falls within the parameters called for by a certain commercial canister grade, then it is sold under that label and number. If not, then it is usually sold in bulk to an ammunition loading factory which adapts its loads to the characteristics of that lot of powder. That is why most factory loads cannot be simply duplicated using a cannister grade powder, because the powder they use is typically slightly different from the "identical" cannister powder. (Of course, what self-respecting handloader would WANT to duplicate a factory load? )

I'm not aware whether the spec-ed parameters for RL-22 and MRP are identical, but they are very, very close; so close, as JPB notes, as to overlap from lot to lot.

As to relative burning rate tables, I've never seen one that didn't have glaring mistakes, and never seen two that agreed with one-another. This is, in part, because some powders behave very differently with the size of case in which they are fired and the weight of bullet that is resisting their force; but most "relative burning rate" tables are the result of someone's largely arbitrary opinion. In the instant case posted on this thread, for example, 5010 is consistently slower than 7828 in spite of where it is positioned on this table.

Great Powder that Reloader Series, made in Sweden same as Norma, but it is not the same powder, but very close.

N201-RL7
N202-RL12
N203-RL15
N204-RL19
MRP-RL 22
MRP2- RL 25

I too was under the impression that MRP and RE 22 were the exact same powders until I used RE 22 in a hot 7X57mm Mauser load that I had originally developed with N205 and changed to MRP when N205 was dropped.

In my experience, the same weight of RE 22 occupies MORE space in the case than MRP, BUT with the exact same charge weight, produces the same MV as MRP does, and at much lower apparent chamber pressure!! So maybe it is the "same", but not exactly the same! As Ricciardelli shows above, RE 22 does seem to be a little "slower", at least as far as peak pressures go, even when developing the same MV in the 7X57mm. Of course, we all know that relative burning rates of various powders can change as calibers, bullet weights, and case capacities change....

[ 07-24-2003, 18:21: Message edited by: eldeguello ]