The temp of the rifle plays a big part too.
I know that's why I placed the rifle in the truck too, after about a hour I took both out and waited to the ammo cooled to 105 degrees, fired over the crony and average fps with 2 rounds were only 69fps over the worked up load in 30 degree weather, and I'm already running hot on this load of 46.5grs of RL19 and sierra 95gr matchking, remington 9 1/2 primer, winchester case and bullet seated with bolt closing, no flat or crater primers, no heavy bolt lift, no ejector marks and the two rounds I fired touched at 100 yards.
