My experience with Reloder 25 is it is slightly slower burning than Rl26 in bigger cases.
I have two barrels now that love it.
30 Nolser with 200gr Berger Hybrid and 300wm with Berger 185 Hybrid.
The 30 Nolser is about 98% case fill. The 300wm is compressed at about 105% but this barrel prefered .100" off the lands.
I have enough to last these two barrels plus one more. My RL25 was bought when it was under $30 a pound.
I have already been preparing to replace Alliant with Vihtavuori in the future.
$62 a pound is way past my pain threshold!
Used it for the 7 Mag eons ago, worked well with the Swift Scirroco 150 grain and the 160 Accubonds. To my experience, its not as temp sensitive in the cold as it is in the heat. From 75 to 95 degrees, I would see a jump in velocity and a little hard bolt lift, but overall I have harvested a bunch of animals with it. Did not bother me at all since I hunted in winter.
A Hornady max book load gives an average of 3003 fps and .58” groups with a 175 grain ELD-X from my 7mm Rem Mag. The rifle has a 26” X-Caliber barrel. The load was worked up in 85 degree temps but shoots just as well in 30 degree weather but I didn’t chrono it again in the cold.