I am sure many of you have seen the warning on powder not to leave it in your measure, always store it in it's original container.
About 6 weeks ago I was working up some loads for my .308 with Varget. Got up to 2800 velocity with 46gr , got interrupted and didn't get back to loading for about 6 weeks. Started again with the powder left in the measure and chrono'd 2675?? WTF?? got some fresh powder out of a 8lb keg, same load back to 2800+.
As a experiment I weighed out 46 grains of varget and left it in the scale pan for a week...it now weighed 48.5 gr It has been pretty humid lately especially in my basement and I am pretty confident the powder absorbed moisture. If the powder in my measure absorbed this much moisture it would of in effect reduced my charge of 46 gr. by 2.5 gr. Hence the lower velocity.
Something to think about.
Lefty C
