Lot to lot difference in Universal

[fatelk]

I have several pounds of Universal in my powder magazine and have found a load I like for the .40 S&W with powder coated bullets.

I recently emptied a can and opened another to find powder that looked different. The old was a light color whereas the new is red. Looking closely at the almost identical cans, I see that the old was made in Australia and the new is made in Canada. No problem, but I wanted to check a few over the chronograph and at a target just to make sure.

I was surprised at the difference. The old powder clocked around 980fps, whereas the new powder averages just over 900fps. Same load, bullet, etc., same day. I had to adjust the powder measure slightly due a small difference in density. No big deal, I'll just spend a little more time to work up a load I'm confident with for the new powder. I was just wondering if anyone else had noticed this type of variation in what is supposed to be the "same" powder. Yes, I know it's not the same seeing how it's made in a different country by a different company in a different plant, but it seems that one would expect it to be the same formulation with closer to the same performance?

[shdwlkr]

fateck
you said,"but it seems that one would expect it to be the same formulation with closer to the same performance?" Why would you expect this? As you stated it is now made in Canada and who knows what chemicals are available in Canada to make powder, how the powder master sees the powder should be made, there is a reason we are told to start to work up new cans of powder as they are not expected to be the exact same even if made by the same company. When you change manufacturers it is to be expected to be a totally new game. I have never seen two different lots of powder from the same factory act exactly the same. there are just to many variables when making powder and one doesn't make this stuff one day and sell it the next.

[fatelk]

Yes, I expected a difference, I just didn't expect just a big difference. 10% less velocity for the same charge in this particular load surprised me a little; I guess that was foolish of me.

No worries. I really like the powder. I'll just tinker with the load a little and keep using it.

[35remington]

fatelk's observation of this much variation seeming excessive is pertinent.

Possible you did something different to account for some of it as well?

My own observation of Universal as that it is excellent in some cartridges but very poor in others. It is one of the most position sensitive powders extant, particularly in larger capacity low pressure ones.

[dverna]

The whole point of using canister powders is so you do not need "test" when changing lots. Something is wrong.

[Boogieman]

I found the same with Titegroup. One lot was slower & heaver for equal volume. The faster lot heated the barrel & brass more.

[dragon813gt]

The whole point of using canister powders is so you do not need "test" when changing lots. Something is wrong.

Says who? There will always be lot to lot variations so you must test when changing. They're supposed to be w/in a certain percentage but the manufacturer is the one who determines this.

[fatelk]

Well, I'm a little embarrassed. I did a little more careful loading, and the resulting difference is not quite as large.

I pulled a couple of rounds loaded with the old powder apart and they were slightly over my nominal load, by nearly .1gr at most. The new powder I worked up to that same nominal load, but they were ever so slightly under, for a total difference between the two of perhaps .15 grains at the most. The new powder still clocks a little slower with the exact same charge, but only on average maybe 30fps or so, well within expectations and definitely not worth grousing about.

I'm a little surprised that a tenth of a grain makes such a difference. I worked this load up to be around factory ballistics, but not "hot". I wouldn't want to get careless and bump it up any.