[The Bolt Man]

Have any of you out there had problems like the ones my shooting buddy and I are having.

My shooting buddy and I have been working with AA 5 and AA 7 loads in the 357 Magnum and 9mm.

We have found a significant difference in the energy of loads using his batch of powder and mine. I ran into the same problem when I went from using a one pound can of AA 5 and AA 7 to using AA 5 and AA 7 out of eight pound jugs.

Loads that performed well without showing pressure signs suddenly started to flatten and crater primers and had to be backed off three to five tenths of a grain. I pulled the bullets from some of the AA 7 loads that were now too hot and noticed the powder didn't even look the same. The powder from the one pound can was all very small ball powder and the powder from the eight powder jug was mostly small ball but also had some flattened balls with it.

I called Accurate powder asking for an explination of the problems we were having. The first answer was in regard to the different appearence of my two containers of AA 7. The powder with the additional flatted balls is simply the way they adjust the burn rate of the powder to match the burn rate for that type of powder. As for my experience of significant difference of burn rate with one pound verses eight pound containers, the suggestion was that I probably unknowingly changed something like crimp, seating depth, brand of primer etc.. I DIDN'T.

Now I am not very happy with the batch to batch quality of Accurate powders. Unless I come up with some loads that I can't match with the good old standard powders, I won't be using Accurate powders when my present supply runs out.

I haven't run into this problem with Unique, 231, 700X, 2400.

 

[Rocky Raab]

Until recently, Accurate tended to switch suppliers chasing the "low bidder" dream - and sometimes because sources simply dried up. That led to a lot of variation between batches, some of which actually forced slight name changes in the product, such as when #2 changed to #2 Improved and then BACK to #2.

Now that Western owns Accurate, they have pledged to end that kind of thing by sticking with one supplier for a given powder, and increasing their quality control.

By the way, as to the company and product names: Originally, it was Accurate Arms, until a gun company with that name trademarked sued them. Then Winchester sued them about the "AA" designation because they have that trademarked. So now, we should use Accurate Powder, and call the products Accurate No. 5 or Acc #5

 

[The Bolt Man]

Great explination. Now I understand why I have been seeing so much variation. I hope this problem is now resolved.

 

[Rocky Raab]

Look at the labels. There should be a country of origin statement, as "Made in Belgium" or such. If they are different, you can just about assume the powders won't be identical.

Accurate powders have been made in Scotland, Belgium, France, Israel, Czech Republic and South Africa - that I know of!

 

[GMFWoodchuck]

This seems silly to me. That a powder "manufacturer" would use difference sources for their powders. How would they know for sure that the reloading data is good? Or safe for that matter....

Hopefully they stopped that for good....

 

[Rocky Raab]

I don't think that Accurate ever described themselves as a "manufacturer" but rather a distributer. Western (Ramshot) is the same, and so is Hodgdon. None of them make powder at all, with the exception that Hodgdon does manufacture their blackpowder replacement propellants. ALL the other powders under those three names are bought, repackaged and distributed. Alliant manufacturers their handgun/shotgun powders, but imports or buys all the rifle powders.

One reason why load data changes is precisely because powders change, and testing reveals that. Test methods also change, as do the parameters/limits being tested to. All these things taken together is why all sources of load data insist that only the most current load data be used. This habit some people have of using load books from the 70s because they list heavier loads is foolhardy in the extreme.

On that topic, Accurate has just released their newest load data, version 3.5 which DOES contain a lot of changed loads. It supersedes ALL previous data for Accurate powders. Download it here http://www.accuratepowder.com/

 

[hogcowboy]

This habit some people have of using load books from the 70s because they list heavier loads is foolhardy in the extreme.

I've thought the same for years. That's the reason I get a new load manual whenever a new one comes out. There are other forums that swear the powder stays the same. Thanks for the explanations. I'd rather be safe.

 

[GMFWoodchuck]

I understand why a new book "should" supersede an older book. But what about when dealing with an older powder. Suppose I had some stuff (I don't) made a few years ago before the change in manufacturer. You can have all the new testing methods you want, but there could be differences in the powder. Does that mean use the old book?

 

[Rocky Raab]

Yes, it does. I do exactly that when I come across a long-gone powder. For that special instance, we might say to always use the most current manual available for a given powder or component.

I have and use significant quantities of W230, 630, and 680; Alcan 5, 7, 8, and 120; Herter's 102; Scot Brigadier 4197, 3032, 4065, and 4351; and Scot 1250. Plus older and changed versions of Nitro 100, Accurate #2 Improved, Bullseye, 2400, RedDot, and probably a few more I can't recall right now. I try to find data current for the date of that powder's manufacture date, if I can determine that.

Complicated? Yup. Time-consuming? You Betcha. But my time is a lot less valuable than my body parts!

 

[GMFWoodchuck]

Maybe 'll stick with shooting it as fast as possible!!

 

[joej]

For what it’s worth, I can tell you what some of us did while shooting benchrest. When we ran out of one lot number and had to go to different lot number using the same powder – all we did was set up the chronograph and use whatever charge that brought the velocity back to where the other lot number was.

This more often than not resulted in the same bughole groups and only took a couple rounds to get back in the game.

I’ve never been concern with handgun powders but maybe I have a new excuse now for some of those lousy groups I shoot every now & then.

 

[The Bolt Man]

Thanks for all the good information.

I am glad I made it a practice to put the date of purchase on my powder and primer containers. From what I see in these responses, I should be trying to use loading manuals that date in the same time period the powder does.

I am still using some powders that were purchased in the 1970's and 1980's, mostly Bullseye and Unique. They still perform just as good as they did when purchased. Most of my other powders were purchased in the 1990's and later. I usually buy my powder in 5lb. or 8lb. containers so I am not switching lot numbers so often. If it is a powder I use more of, based on my average annual consumption, I purchase enough to last a number of years.

 

[unclenick]

Rocky's covered the issue really well. I'll only add that Hodgdon says they blend to keep burn rates within 3%. I don't know if that's extreme spread of +/- 3%. I'll have to ask. Just looking at the measured data in QuickLOAD you see 10% difference between 296 and H110, even though they're the same powder. The two measured lots just weren't the same.

The practice of matching velocity with a different lot of powder is only safe if the new lot isn't very different in burn rate from the old. In principle, the faster of two powders producing the same velocity will have higher peak pressure and lower muzzle pressure. If you get the same bugholes with the adjusted load as with the old, that's a good sign, as it means the barrel time has come out the same. That only happens if the pressure curves are a good match. If the adjusted new load was not a bughole, that's a sign the burn rate difference is excessive for this practice.


Rocky,

Wasn't that Brigadier powder great stuff? I still have some 3032 and 4065. Some of the best .308 and .30-06 powders ever made, respectively. Just sorry their insurance didn't rebuild the plant after the fire.

 

[tnekkc]

When we buy resistors or capacitors, it has a percentage accuracy printed on the side.
I wish they did the same with canister powder.
H4350 is not as good as Varget for consistency.

 

[Rocky Raab]

In my discussions with powder people like Chris Hodgdon and Ben Armonette (ATK), I've learned that SAAMI allows a 5% variation between lots of a given powder, but that powder companies strive to keep that to 3% - for obvious reasons. That's in burn rate, but tested in a closed bomb, not in cartridges. So even though a powder meets its 3% in tests, it may not perform that way in a given cartridge combination. ANY other component can and does alter the burn rate. So does gun temperature.

Knowing this is why I developed my 95% Solution: http://www.reloadingroom.com/index_files/95S.htm

The most important thing about my method is that that it allows you to discover just how much a change in components affects YOUR load - without the danger of firing even one shot that is too hot. It also minimizes waste of what are becoming increasingly expensive components. Very useful, that.