I don't think RL17 is temp stable. I tested it with the old put some in the cooler method. I did this side by side with RL17 and H4350. H4350 barely changed. RL17 change was about 1.5 degree per 1 degree temp change. Alliant does allude that RL17 is temp stable on the can, but I believe they are really saying that it will still ignite well and have plenty energy for bullet performance at lower temps. I think this is true because one member on the forum has pressure traced RL17. RL17 has a very long power curve, it doesn't spike like H4350 so you can get a lot of speed out of it. RL17 is 75+ FPS faster than H4350 in some of my loads.
Now, seems they are flat out saying RL16 IS temp stable. If that is so, and it has a power curve similar to RL17, it might be a winner.