The ambient temprature do play a big role in the preasure. I am not familiar with the different propelents you use, but extruded propellants are less sensitive to ambient temprature changes than ball propellants. I swithed to extruded propellants about 2 years ago and never had presure problems or a major shift in point of impact.
-------------------- Life is how you pass the time between hunting trips.
Sometimes I do not express myself properly in the English language, please forgive me, I am just a boertjie.
Jaco Human
jacohu@mweb.co.za SA Hunting Experience