Oh fiddlesticks, there is a difference between powder lots

[Questor]

I use Winchester 760 for some favorite loads, and as part of the load data I note the micrometer setting to use for my powder charges.  I just got a new jug of 760 and the same micrometer setting I have been using all along now yields a charge weight one grain heavier than it was with the old lot of powder.  This caused a problem when I topped off the powder measure with the new stuff and it affected my charge weight.

During the same session I started using some new brass with a new lot of Nosler BTs.  My overall length was about 5 thousandths longer than with the old brass and an earlier lot of the Noslers.

[Flint]

The powder makers test for pressure and velocity by weight.  Most reloaders measure by volume.  If you reload by weight only, canister lots won't affect you.  Every time you buy a new lot of powder you MUST test the new lot with a powder scale and reset your measure.  Mixing old and new powder lots in the measure is not a good idea unless your loads are well below maximum.

[Carl l.]

That's good advice Flint. I have a powder measure but I have always weighted my powder. I know it takes longer but then I know how much powder I put in the case. When I load 200 rounds or more at one time I set the powder measure light and use a trickler to finish it off. That is just my way I guess. Carl L.