Count me a fan of RL26 aka "pixie dust." I've used it in a 270 w/150s, 270wsm with 140s, 7mm08 with 160s, 7STW with 160s, 300wm with 200s and a 340wby with 225s. I've yet to experience pressure spikes but I typically won't shoot if it's hotter than 80. It isn't always the most accurate load, but it's always been the fastest by a significant margin. My problem is I'm down to about 4lbs of it….. I'd hoped to do additional testing but presently feel compelled to conserve what I have. I will note that it seems to run dirtier than most powders I shoot.
Great to have a PLAN B on your favorite powder choice, as we have had to do with R#15, 22, 23, 19, and 25. The WAR is not getting better in Europe with Russia and China buying up all the gun cotton being produced, better get what you can.