My go to load with 123 grain bullets (Nosler CC, SMK) is 31.0 grains CFE223 and CCI 450 in Hornady cases. Ive shot this load at 90 degree temperatures without issue. Here are the velocities I got on a 75 degree day using a Magnettospeed chronograph.
Hand Load 123 Grain Nosler CC, 31.0 grains CFE223, CCI 450
16" 2449
18" 2471
20" 2526
24" 2619
Everything Ive read expect about 1.5 - 1.7 FPS of velocity change per degree of temperature change. In essence 40 degrees compared to 70 degree the CFE223 will produce about 50 FPS less velocity for the 30 degree cooler temperature.
Hand Load 123 Grain Nosler CC, 31.0 grains CFE223, CCI 450
16" 2449
18" 2471
20" 2526
24" 2619
Everything Ive read expect about 1.5 - 1.7 FPS of velocity change per degree of temperature change. In essence 40 degrees compared to 70 degree the CFE223 will produce about 50 FPS less velocity for the 30 degree cooler temperature.