Norma MRP temp sensitive?

[A guy named Bob]

Bought a pound this morning from powder valley. I have a new 6.5 PRC that I want to test with this powder. What are your thoughts as to temperature sensitivity with this powder? Thanks for any help

 

[cdherman]

I have what's left of an 8 lb jug of MRP that I bought at some vague point in the last 10 years. I tried it in a number of guns and never was quite happy enough. I never had a complete temp sensitivity disaster, but I don't load hot. But I did not get session to session accuracy retention that I would like.

IIRC, I read a LOT about temp sensitivity, as I hunt in Kansas, where it can be zero in deer season, and it might have been 95 when I developed my loads. MRP was reputed to be better than some of the Alliant powders (the old one's like RL-22) in terms of temp sens, but not as stable as the Hogdon temp stable series (H4350, H4831, H1000 etc)

There also were rumors that MRP was the SAME as RL-22. This is not likely true, but they are very similar powders in terms of burn rate and density.

 

[A guy named Bob]

Thanks

 

[Mike Matteson]

I use MRP in my 25-06 with 120 gr ballistic tip Nosler for years in hot and cold weather, and never had a problem with it. In the fall and winter I am planning on running some test with it. If I get my move done quicker I will start this summer, when it's hotter. A long time ago I used the load from Nosler reload manual in hot weather in S. Cal, and used it during the fall in Cal and winter in Nev, and Utah, Montana. but I wasn't really looking at that possible problem. I talking about in the late 70, into the 90's. I move up to a 308 Norma Mag in 2000. I got an upcoming with IMR powders then. I gave away the IMR powders and never used them again. So there some info, but not really enough to be sure.