Variances between powder lots

[Bergcrane2]

I know the powder manufacturers say to start with a minimum load when using a different lot of powder, even if it's the same powder, and work up to a load. BUT, has anyone seen differences between Lots? How unsafe is it to just jump in and cook up a batch of your favorite load with a new lot?

[glenn asher]

Spherical powders are more prone to changes than stick powders, sometimes H-335 can be pretty spooky in different lots. I seldom run my loads too awfully hot, and have never had any troubles, but I have noted some spooky stuff with certain pistol powders.
Then, too, some flake powders from Alliant (the old Hercules company) have been changed a lot over the years. Unique was changed considerably some years back, so it would burn cleaner, I think 2400 was changed, also. I haven't used them since the changes took place, but it was recommended to back them off quite a bit when starting with the newer stuff. Supposedly, the newer powder was engineered to give the results of the older propellents, but sometimes "things happen". It's good advice to recheck each time you change lot numbers, I think. (it's also a good reason to buy those 8 pound jugs!).

[Bergcrane2]

Good point about buying the 8#ers. I'm using RE10X right now. Being it's a fairly new powder, you'd think they may play with the formula a bit. I'm running lower than I thought and I have 200 new 39gr SBK's and brass coming tomorrow from Midway.

[jo191145]

In the past R-10x had a reputation for some drastic variations between lots. Silverfox ran into some trouble with it. Always best to drop down a bit and work up.

[bk63044]

All of the powders that I have checked has had some variations lot to lot, it may be just a very slight variation. Powder as it gets older can also change. We spend alot of time to see that our powder stock is rotated properly. Where I work we always have over a 1000 pounds of powder in stock all of the time, so it can be a chore.

[Verminator2]

Well, the powder that I used to shoot those groups with was probably over 5 years old (IMR 4895 that came in a tin can) I picked some new powder up. Do you think that this new powder would make much of a difference in my groups?

[WrzWaldo]

Well, the powder that I used to shoot those groups with was probably over 5 years old (IMR 4895 that came in a tin can) I picked some new powder up. Do you think that this new powder would make much of a difference in my groups?

Yes, No, Maybe?


You really won't know until you shoot some.

If you are loading near the top end of the published data you will probably want to back off a couple percent and work back up to your current load.