I went to the gun store today to order some reloading stuff. I got into a discussion with the salesman (who also owns a 300 WSM) about powder. He pointed out to me that some powders... for instance Win 760, are affected significantly by temp cahnges. He said Win 760 looses 2 fps for every degree of ambient temp change. Sooo... if one works up a load on a 50 degree day and goes out to shoot an elk on a zero degree day, that would add up to a loss of 100 fps...plus...the affect on pressure, which has to have a significant affect on accuracy, ie. yer bullet will probably have a new point of impact. He recommended the Hodgdon extreme powders such as H4350 to me because they are not affect by temp changes. If this is true why even bother with any powder that is affected by temp change? I think I have narrowed my potential powder list from 5 to 2. Comments???