RL22 is in a section of the library all by its self, it's awesome some but she's dangerously touchy with temp changesAs far as external and terminal ballistics yes, it doesn't make that huge a difference. Internal ballistics Can be another story. I think it's best for op to keep doing what he's doing. Work up max loads in the hottest conditions you'll work with. No nasty surprises later. Not that a big temp jump would make a round dangerous but I have personally experienced hot loads in my 270 with Rl22 (when I was a rookie at this) that functioned flawlessly with no pressure signs worked up in January (between -20 and -35 celcius, Saskatchewan) make the same rifles bolt very sticky indeed in June (generally between +20 and +30 celcius). I know where I live sees way bigger temperature variations than most places but it applies all around - so to the OP...just keep doing what you're doing. Better to find the limit in the heat than in the cold.