Carnauba Red holds up just fine in the 110*-115* summers we have here in inland southern California. I don't shoot once the temps hit 100*--I'm not immortal anymore. But back when I did, the C-Red held up fine while shooting in 100*+ temps in 22 Hornet at 2400 FPS, in 30-06 at 1800-2200 FPS, and in 9.3 x 62 from 1700-2100 FPS. All three calibers did good work using C-Red in more moderate temps as well. It is my rifle lube for any bullet running 1400 FPS plus.
Alox/BW 50/50 does not "melt out" in 100*+ temps, even when loaded rounds are stored in bulk in coffee cans. They have yet to foul powder as far as I can tell. I have used it since 1985.