I've had issue 7.62x51 Nato ammo blow primers - drop out upon extraction from my match rifle - the ammo box was sitting in the sun on the pad, lid partially closed. Sun peeking in one side was enough to boost it well over safe.

The Hodgdon Extreme powders work well for me in heat and cold. For example, H4895 (ADI2206H?) gives me within 20fps. from +80F down to -10F. I was happy with that. I expected 100fps or more drop, like I get with Hodgdon's Lil'Gun in the .218Bee. I guess they didn't lie - about the Extreme's being temp stable. Too - ammo loaded up hot (high prssure) in the winter with that powder and Varget, didn't react any differently when shot in the summer.