Load development, and temperature

[Hunt7112]

Looking for some advice.

 

Developed my load for my 7mm RUM in august-early september shooting in the early mornings and evenings temps were in the high 80's to low 90's was averaging 3360fps shot yesterday with the temps 67-68 degrees the chrono was avg of 130 fps slower is this to be expected, and should I work and develop this load to match our weather during hunting seasons.

[firstcoueswas80]

That is pretty normal. What powder are you using?

 

 

Alot of people claim powders show no temperature difference, but I fail to believe that.

[Hunt7112]

IMR 7828 federal 215 and 150 sciroccos

[308Nut]

I typically test my loads hot and cold, average out the FPS/degree loss or gain and adjust my calculator velocity input for the corrected velocity based on the current temp.