Powder lot variability

[keithcatfish]

After quite a bit of experimentation, I found an exceptionally accurate, mild load using an older lot of Varget. I recently used up the last of the old lot and purchased an 8 pound jug of a newer lot. Using the load developed with the old lot, my groups with the new lot have grown about 50%. Powder lot # is the only variable that has changed.

Is this normal? When I work up a new load, will it shoot as well as the old load?

Thanks for your help,
Keith

 

[Travelor]

VARGET is great powder but does vary from lot to lot. Sometimes more than other times. Sounds like you got both ends of the load speed variations of VARGET.

If you have the velocity of the prior load, you should be able to get you accuracy back by loading to that velocity again. BTW, this works with Seasonal changes if you load starts to open up,or tighten up).

Good luck and let us know how it works.

George

 

[Linefinder]

I've never had 2 different lots of the same powder exhibit the exact same burn rate.

When I get a new container of powder, I load 5 rounds each of a low and near book max charge weight and chrono them. I then can back into the burn rate via QuickLoad. This gives me a much more accurate basis from which to experiment.

For high volume pdog loading, I buy,2) 8lb jugs online at a time. When ordered in this qty, both jugs are packaged in the factory box, and are always of the same production lot. This sure cuts down on testing/tweaking time.

I don't bother with this method for the less used big game rounds.
The initial test from the occasional new pound of powder isn't a big deal.

Mike