Stumped, was curious about temperature change coinciding with powder load and group size. Never fails, spring time I get my powder load shooting a 1/2" and as the summer wears and temp goes up so do my group sizes. I've gotten to the point where I only shoot three shot groups thinking that the barrel is getting to hot or the mirage off the barrel is screwing with me. But then I got to wondering if a 20-30 degree difference is what is effecting the group size (Iowa aka hot and humid), driving me nuts to the point I start testing loads again. Been shooting and reloading every week for the past five years now and still learning (at a slow pace mind you, hahaha). Looking for some pointers.