I Load for 280 ai w/160 gr and will be starting 300 win mag where I plan to use 180 or 200 gr bullets.

Suggestions on any of the new IMR or Alliant powners. Would like a powder yhat works well for both. Worth looking at? Open to duggestions.

I'm not familiar with IMR 4931.

IMR 4831?

Stable as in heat sensitivity, or longevity? I have a batch of 1960's vintage surplus H-4831 that shoots as good as the new stuff. So, stable as in lasting forever...?

The new IMR 4955 powder is reportedly fairly temp stable with the Enduron Technology with a burn rate similar to 4831. Haven't used any, just going on what is claimed.

H-4831 is going to be less temp sensitive than IMR-4831. I've seen data on the IMR version that shows temp sensitivity, the Hodgdon version is the Australian Extreme series and is reportedly less sensitive.

Enduron powders are made in Canada and it seems they are shooting for the same goals as the Extreme series.

I've not seen comparisons between Extreme and Enduron powders.

DF

They say RL23 is more temperature stable then RL22 with similar burn rate. Going to try it in 300 H&H when some gets available.

Keep it simple, H-4831 is an "extreme" powder with low temperature variation.

R-26 is supposed to be minimally affected by temperature change around 0.5 to 1 fps to degree change.

Sorry, I meant 4831 and temp stable. Velocity with H4831 was poor with the couple of lots I have trued. I did use it with 140s in the 280 but was not happy with accurate speed.

IMR 4831 had better speed, accuracy great and what I am using with 160 accubonds now. R22 fastest and accurate but squirrely in hot weather.

I picked up a pound of 7828ssc to experiment with but was wondering about newer powders. Checking if anyone had tried R23,R26 or the Enduron powders in a 280 or 300wm or which might be the best bet.

Thanks

Both H1000 and Retumbo are temp stable with a burn rate similar to RL22 and IMR4831

I just bought 3lb of R 23 which is supposedly pretty close to 22. Tried it in my .260 and it was a little too slow to get top velocity with 130's.
Intend to load some up today with 180&200's for my .300 win mag. I suspect it will work pretty good based on the data I have seen.

Lefty C

I got better velocities using IMR 7828SSC and Magpro versus H4831SC in my 7 SAUM Model Seven using 160 grain Accubonds.

Ridgerunner on this forum was trying R26 in the 280AI at about 61 grains with the 168 ABLR or Berger (I think?). He was pleased with the temperature stability and accuracy. Maybe he will post a follow up.

No idea what the pressure is but someone else worked up to 62.5 but then backed way off thinking it was almost a proof load in their rifle at that charge level.

I am going to try it with 140s and 150s at some point. But may load for the .270s with it first to get more familiar with R26 before going into uncharted territory.

I get a little uncomfortable with many "new and improved" products, as that often tranlates to " we found a cheaper way to make it."
We enjoy powders like many of the IMR line, bullets like Partitions, that have withstood the test of time.
For example, there products like Winchester 785 (good stuff), WMR (not so good), that had several poor iterations or Barnes & Nosler bullets that got dropped for "new and improved" generations. Reloader 15 and 22, while wildly popular, have had problems, and are likely in the process of being replaced.
Yes, I understand that change is inevitable... eventually. Occasionally something is actually made somehow better, but much of this is simple marketing foo-foo.
I recognize myself as a card carrying luddite! My loonie impulses are not what they once were.