I have used MRP for the past 25 years in two custom .340 Wea Mags with great results. MRP has been extremely accurate, very little deviation and near factory level velocities.
Recently on a discussion on another forum a member stated that absolutely, positively RL22 and MRP are exactly the same. You know how sensitive and opinionated some members can get so I did not respond. On this forum I have read several posts about MRP and RL22. One member here actually posted close up photos of the kernels of both powders showing obvious differences. I know they are both manufactured by the same company in Sweden.
I apologize in advance if you have already answered this question(s).
Are MRP and RL22 exactly the same powder with just different labels?
The MRP has never shown any temperature sensitive pressure issues having fired hundreds of rounds in 100+F and 10F temperatures with at least 8 different lot numbers over a 25 year period.
Are there differences in the treatments of the two powders to handle temperature sensitivity?
If they are the same powder have they always been the same?
Any other differences?
Thanks!
NWT

Not MD, but are they exact? No. They are kissing cousins so close to each other that it’s my belief that RL22 is actually MRP seconds or blemish whatever you want to call it. I’ve interchanged 22 and MRP in a 25.06 for many years.charge weights are nearly identical, performance is also nearly identical. Where it varies is consistency lot to lot.

Buy and read Gun Gack II. Happy Trails

Look at p. 75 in GG 2

MD says they are the same, I do not and one technician from Ramshot said definitely different powders. But they are so close they usually can interchange with allowances for lot to lot variation. My understanding is same base powder but different retardants used, also MRP is more uniform in all ways: lot to lot, grain size, burn rate. I don't know if there is any difference in temperature sensitivity but if there is the slight edge would go to MRP.

Both came from the powder used in 6.5x55 Scandinavian military loads, first with a 156 grain bullet and later a 140 grain.

Quick load says they are not the same.
But it also says ADI version of Hodgdon's powder are different as well, so go figure.

The instance I reported on in GUN GACK II took place several years ago, when I did an article for Handloader magazine on the .270 Winchester.

The batches I had of RL-22 and MRP at the time looked exactly alike, and got the same muzzle velocities, with the same bullets, in the pair of test rifles I used, a Winchester Model 70 Featherweight O'Connor Commemorative and a Ruger No. 1B.

Not too long before doing that article I had talked with the head of Norma at the SHOT Show. He admitted that MRP was the same powder as RL-22, but that he believed MRP was more consistent from lot to lot.

From all that I felt comfortable in claiming they were the same powder--at least at the time. One or both may have changed since then.

Thanks everyone. Some great information. Some conflicting information too.
It sounds a little bit like we know what we don’t know.
Anyhow sounds like they are equals in most ways. I will just continue to use MRP as long as it is available.

Probably half the people on this forum are wondering........WHERE is MRP available at so we can get an 8pounder before Biden gets in tomorrow ?????????

I saw a new burn rate chart the other day and there was a powder between MRP and RL22. I do not remember which it was (Magpro maybe), but that would infer they are different

Lou

BA,
Should have said as long as they continue to manufacture it (MRP).
The Swedes didn’t shut down their economy so if Norma doesn’t absorb all of the powder we might
be seeing some down the road.

Look at Nosler’s website loading data for the 30.06 180 grain. It shows 62 grains of MRP @2710 FPS and then shows 62grains of RL22 @2810FPS.
Just adds more to the confusion .

You should add Winchester WXR to that list

Yes,from what I had read in the past MRP,Reloader-22 and Winchester WXR were all made in Sweden at the same factory.Reloader-22 and Winchester WXR were same powder as MRP that did not make the MRP specs.Winchester WXR was discontinued around 2012 and was replaced by Winchester ball powder 780 Supreme.I never shot any MRP,but I did compare Reloader-22,WXR and 780.With the same charge in my 7STW,Reloader-22 was really close to WXR.WXR ave about 15fps faster and that's really nothing.You can have that much difference in the same branded powder of different lots.They grouped the same with my loads.780,now discontinued too,was a bit slower,around 40fps with the same charge weight.I'd say it is probably close to IMR-7828.

Strange if MRP and Re22 are the exact same powder, that MRP is more consistent from lot to lot. ??? Do Norma apply more quality control when making their own branded powder and slack off a bit when making Re22?

Why wouldn't the two powders exhibit the exact same tolerances if exactly the same powder?

Agree with you 100%.

When the run of Re 22 is made the reject box has less powder in it

I suspect they arise from the same production line, but are separated by testing. This is not uncommon in various industries. For example, in electronics, different resistors are not made to be 10%, 5%, and 1% accurate. They just make one kind of resistor, then separate them into the different groups by testing for accuracy. (And charge more for 1% than for 10%.)

I once saw a burn rate chart with another powder between W296 and H110, also.
Burn rate charts are an approximation, and burn rates can change slightly in different calibers - so I'm told.

Norma's V2 Reloading Manual has a burn rate chart that shows Reloader 22 at Relative Velocity 90.2 and Relative Pressure 81.1 and MRP at 89.9 and 80.1 respectively. Chart is from Eurenco/Bofors...

You'll see that much variation, lot to lot, same powder.

DF