Bob you will have lots of time to shoot Friday. We can talk about all that stuff Thursday evening when you get in. I will be in Selkirk Thursday evening as well.
The Basic theories:
We load by volume. Supposedly the powder burns by weight. So in theory, when it is cooler out the size of the kernel gets smaller. Basically the expansion and contraction factor.
Again in theory, your load in the AM will be slightly less than in the PM. Then there are all the other factors that come into play. The temperatures and humidities effect on the burning of the powder. What I find the best way to see if your load is going south is shooting at 200. Unfortunately you do not get that option when a match is happening at 100.
You can even throw in to make it more confusing is why would I add more powder when it is getting warmer out?
Ideally it would be nice to shoot a match over a chronograph to see what happens through out the day as you try different things. Maybe one day I will have the chance to spend a nice summer day at Selkirk and try that.
You need to be able to trust yourself that you are doing everything right at the bench. No bad bench etiquette, and that you made the right decision on when you pulled the trigger. Then and only then can you let your targets tell the story.
Will have lots of time to talk through the weekend. Don't get to caught up in the load changes. I find that in our neck of the woods things do not change a whole lot. Temp is pretty consistent from Rosebud to Selkirk.
The only diference is you are not in the nose bleed section when you shoot in Selkirk.........