I use RL22, and always have, in the AI and the standard 280. Never once had temp issues that were significant enough to mean anything.
If I was starting from scratch, I might try RL23 for the added benefits. 26 might be a little bulky and slow for that cartridge.
Not sure that RL17 will have any less temp problems than 22 does, actually. I did run some H4350 with 120 grain loads, but stopped using that bullet. I just use one bullet and powder for everything now in the AI, and it works perfectly. 145 LRX.
