Originally Posted by drpbroun5
I have heard alot about temp sensitivity in various powders. Has anyone done any testing of different powders to see how much temperature affects each? I have not been able to find any data on this topic. I did a search on LRH and saw some discussion regarding specific powders but none that compared several or multiple ones. If anyone knows of some data on this, I sure would like to get it. Thanks.
Absolutely! There have been many tests on this subject. Many have been published and some data is contradictive but I'll give you my own personal results.
As far as brands go, here's my list from most temperamental to least:
1. Ramshot (because they are all rifle ball powders)
2. Winchester (because they are all rifle ball powders)
3. Accurate (because they are mostly rifle ball powders)
As for individual powders, my list is this: (I'm not going to name each powder here, just a few of the best and worst and a few of the ones in the middle)
most temperamental to least:
Even though some of the powders listed towards the bottom of the list are great for weather insensitivity, they still exhibit a need to tweek with the charge slightly in temperature changes to maintain a certain pressure. Despite some claims by some manufacturers that their powders will shoot the same from 20 below to 120 above, no powder is perfect. Temperature changes all combustables combustion. Period. It is unavoidable no matter what "coating" you use on the powder. And all powders show markedly different characteristics once the temp gets to and above 80 degrees. Loads worked up above 80 will still work accurately as long as the temp stays above 80 degrees. But loads worked up below 80 degrees F do better shot up to around 75 degrees. Or in other words, loads worked up in cool weather hold their node for a longer temp range than loads worked up at or above 80 degrees F.
I'm not sure why 80 degrees is the unlucky number, but I have seen this be the fulcrum of load development time and time again with every brand and make of powder--especially ball powders.