Re: affect of ambient temp on velocity?
Every powder will display different temperature regression results. Some more than others. Sorry I can't help you out much other than suggesting shooting thru a crony at extreme temperature variations to verfiy and establish data for a regression solution. Many ballistics engines allow for turning on or off data regression. I mostly use Hodgdon Extreme powders and zero in temperatures near 40 deg F, an average hunting temperature for my region. This seems to work well enough to where I don't need to consider data regression for a firing solution. If I'm shooting Reloader, a different situation where data regression should be considered for long range first round hit probability.
Shoot CONFIDENT, Shoot SMART, Shoot STRAIGHT