In working up a load for my 7 STW I've found that Reloader 19 is the powder of choice. How temperature sensitive is this powder? I'm going to chronograph it this week and see where I'm at now but I'm wondering what it will be like in -10 to -20 degree weather. What's your experience with it when the thermometer drops? Am I going to lose a lot of velocity or is the accuracy going to go. I know Hodgon has thir Extreme powders that are supposed to not be affected by the cold , but how badly is this powder affected?