I have never bought the argument about RL-17 not being particularly temp stable. Unless you are a long range target shooter in some kind of competition RL-17 is a great powder. I have one 338-06 rifle that will almost shoot in the same hole at 200 meters. As was indicated above I like to sight my rifles in at a mid range temperature of about 50 degrees and I am confident of getting good hits from 20 degrees to 85 degrees without being concerned about the zero. One of the selling points for RL-17 is that it gives the highest velocity at any temperature. You've heard of closet smokers, well I think there are a lot of closet users of RL-17. They use it but don't say anything on the forums because of the negative press. When Alliant powders hit the shelves RL-17 is quick to go. Of course, I am a hunter and not a target shooter and my longest shots are not much more than 300 yards. There is a video on youtube with a shooter in Utah hitting a milk jug at 1000 yards using RL-17 in a 338-06 AI and because it was hot he was keeping his ammo at a consistent temperature in a cooler between shots. I've never been that serious.
Ive had very few issues with it myself unless running close to the edge.
Its one of my 6.5 CM powders when its available, and getting a 140 over 2800 from a 24" tube takes about 42gr of powder.
That load has proven just fine EXCEPT when the rounds are left sitting in the sun, which happened, and they blew primers and locked up the rifle. It could rightly be said that it was user error for leaving rounds in direct sunlight, but thats the only load that did that. 42gr of RL-16 and h4350 were fine. Both of those loads chrono about 2775
Those numbers are consistent over......6 different creedmoor rifles.
Does that mean I think its a bad option, especially when some change in velocity isnt supercritical to success, not in the slightest.
Like I said, it's THE powder for my .375 Ruger (tho Stabal, if i can ever get more, might dethrone it), but Its also one IM more cautious with than some of the other options. That CM load will consistently shoot sub-MOA and ring a 10" gong at 1000 yds from both of the current creedmoors in use, no cooler, just not left in the sun.