Is Pyrodex RS temperature sensitive

[p246]

My trapdoor has been shooting four inch groups all summer and fall. I went out today and it was 19 degrees. I shot a five round group off a bag at 100 yards. Three hit in a three inch group at point of aim. Two hit 12 inches high at 12 o'clock. Its the same load I've been using. The only thing I changed was tightening seating die 1/16th turn to put light crimp for deer hunting. I can't imagine crimp being issue or am I missing something. Load is Remington brass with primer hole drilled with #41 drill bit. 45 grains pyrodex rs compressed, grease card under 505 grain soft lead flat base bullet.

[joem]

I don't shoot Pyrodex RS but I know almost every powder I use is effected by temperature as well as how much crimp is applied if any. I have used the crimp to increase FPS to my desired value. Almost all my reloads are developed around 60 to 85 degrees. Anything outside of those temps affect accuracy. Some reloaders at the club develope loads for summer and some for winter temps. I don't bother with that, too much trouble for me.

[mannparks]

I do use RS and yes the temp will affect the load, but the fact that you grouped three out of five says to me the two out of the group ( high,) were the problem.
We also assume that all five rnds had the new crimp.
Charles

[p246]

Yeah all five built with new crimp. I backed it off and loaded five more and shot them today. It was nine degrees. My group was five inches but was three inches higher than it had been all year long. I'll keep playing with it but it looks like in extreme cold I'm getting more velocity from Pyrodex RS. I had built the load to be on at 100 yes and brush hunt. I think I need to work with it some more. I'll use the K98 or 03A3 for brush this year.