Powder differences over the years?

[Xringshooter]

A friend and I were talking about reloading and I told him I have some pretty old powder that seems to work fine with my older and newer reloading manuals. He told me that if I buy new powder, the loads recommended in my old manuals are no longer safe because IMR powders today have major different characteristics than the old powder. Anyone know if this is a valid concern, or is it just him been being overly cautious? I don't ever start out at max loads and the loads I have been doing have been for my dads 1948 Win 94 .30-30, 28.2 grns IMR3031, 150 grn JSP. Would a new batch of 3031 really be all that different?

[Winger Ed.]

I think the tolerance between one batch to another of a given powder is about 5% or less.

The specifications for bullseye- for example are constant over all its years of production.
If the plant makes a batch from the recipe for it, and it doesn't fall within the specs---
they can't and won't label and sell it as bullseye.

It'll be sold to a ammo maker with the test results and they'll tell them, "Do your own research, but here's what it does,
and it will be good for this..' But none will go into a can labeled bullseye.

It's the same for all of them.

The loading manuals vary over the years mostly due to differences in test barrel or guns, lengths, how much they're worn,
but the batches of powder they use of one label or another will fall in that small percentages of allowable difference.

They try to be 100% true from one batch to another, but its like Grandma's gravy, sometimes it comes out slightly different.

[Xringshooter]

That's what I tried to tell him, the powder makers aren't going to make radical changes to a powder that's been around a long time without some kind of warning (for liability reasons). He was adamant though, "Don't use a new batch of powder with old manuals info, you'll blow something up". I just shake my head and just say "OK" to end the discussion. I've been reloading since 1976 and have stuck with what the manuals say and when I upgrade my manuals (every few years) I cross check what I am loading to see if there are any major differences. So far, there haven't been.

[Winger Ed.]

[QUOTE=Xringshooter;4955382] I just shake my head and just say "OK" to end the discussion. /QUOTE]


That's what I do too.

With a large percentage of the population:
The truth doesn't stand a chance against a well established myth.

[Larry Gibson]

"He told me that if I buy new powder, the loads recommended in my old manuals are no longer safe because IMR powders today have major different characteristics than the old powder. Anyone know if this is a valid concern, or is it just him been being overly cautious?"

It is a valid concern but not for the reason stated; the IMR powders of today are essentially the same burning rates as they were in "the old days". As it was in those old days there was some lot to lot variation but no more or less than today. Powders with different burn rates and burn characteristics are given new numbers. That's why we have a plethora of powders today along with many of the old "standards".

What is of concern is the methods of determining "maximum loads" that adhere to the relatively recent SAAMI standards. Many loads published in older manuals were developed by means other than pressure testing. Even pressure testing via the C.U.P. method is a slow tedious process and only gives a maximum peak pressure. With the advent of piezo-transducer and strain gauge measuring of pressure testing was much quicker and a more complete understanding of the internal ballistics of any load found. Additionally, while voluntary, adhering to SAAMI standards has become a necessity from the legal standpoint. With the more modern piezo-transducer and strain gauge pressure measuring it was found many of the older published loads that were assumed to be within pressure limits were, in fact, way over those limits. Especially with the adopted SAAMI standards. Many previously published maximum loads, even though thought to be safe, were found to give borderline proof level pressures.

Thus we see in many post 1980s manuals many loads with the IMR powders and others that are "reduced". The reduction had nothing to do with changes in the composition of those powders or lawyers but was simply due to the much better understanding of the actual pressures generated that piezo-transducer and strain gauge measurement along with the adherence to SAAMI standards.

[Xringshooter]

Larry,
That's why, if I have older powder, I cross check my new manuals with the older ones to see if there is any difference (major or minor) in the loads I'm going to be loading. I've pretty much always done this.

But to flat state that XYZ powder would be completely different from XYZ powder made 20 years ago is just not thinking or just believing what someone wrote on the internet.

[dbosman]

One nifty feature of the IMR line is that all powders have the same energy per pound. The deterrents and coatings regulate the burn speed and curve. That is what allowed Mr. Powley to create his "computer".

[Dixon700]

There's a much bigger difference in one companies manual to another than there is old to current.

[samari46]

I believe that some years back a change was made to 2400 powder. Loads that used let's say 18 grains of the old 2400 were too hot when the newer version came out and charge recomendations said to lower charge rates when using the newer version of 2400. I have 4 one pound Hercules containers versus the newer Alliant version of 2400. So will drop down about 5 grains and redo my testing. Frank

[303Guy]

My understanding of the updated load data is as Larry has explained.

[1hole]

... the powder makers aren't going to make radical changes to a powder that's been around a long time without some kind of warning (for liability reasons)

That's not only the truth but it should be obvious. When the makers give us new powders for whatever reason they simply give it a new label, to do otherwise would be stoopid and those guys ain't stoopid! But, some of our number do insist on repeating foolish web yarns. I guess it makes them feel more "informed" than the rest of us. Gag.

[Mal Paso]

I believe that some years back a change was made to 2400 powder. Loads that used let's say 18 grains of the old 2400 were too hot when the newer version came out and charge recomendations said to lower charge rates when using the newer version of 2400. I have 4 one pound Hercules containers versus the newer Alliant version of 2400. So will drop down about 5 grains and redo my testing. Frank

2400 hasn't changed except lot to lot variation. I think it was Larry Gibson that tested this. I did get one very warm batch and working up with a new batch always makes sense. They even use the same lot numbers. There have been something like 1,000 batches of 2400 made since the first.

[JohnMcD348]

I have a question, regarding Mr Gibson's explanation of the new versus old powder loads and actually using the newer powder vs the older powder.

If you use the older powder, using the newer load data, could you run the risk of creating a dangerous under load charge?

I don't have any old powder, oldest I have is maybe 12 years at the oldest. I'm just trying to learn what I can about reloading and as much of the aspects of powders and primers as I can, as I go.

Thanks

[gnappi]

I read that Hodgdon stores lots of their powder IN WATER for historical burn rate comparisons. They scoop out a bit, dry it and burn it and compare with a new batch. I'd say they have a vested (likely attorney mandated) interest in not diddling with burn rate changes to a known formula.

[Rich/WIS]

The only time I have seen this mentioned was with newer lots of Blue Dot, but not sure if it was a real issue. Supposedly the newer lots of BD were hotter than old lots. If in doubt use the latest data, doubt if a slower lot would be so different as to create any issues unless you were at a minimum load to start with. Even then probably wouldn't make enough difference to matter.

[Larry Gibson]

I have a question, regarding Mr Gibson's explanation of the new versus old powder loads and actually using the newer powder vs the older powder.

If you use the older powder, using the newer load data, could you run the risk of creating a dangerous under load charge?

I don't have any old powder, oldest I have is maybe 12 years at the oldest. I'm just trying to learn what I can about reloading and as much of the aspects of powders and primers as I can, as I go.

Thanks

"....could you run the risk of creating a dangerous under load charge?"

There is always that risk, depending on the other components, with any powder.... old or new. Any newer pressure tested data will be the best choice to go by.

[Savvy Jack]

"He told me that if I buy new powder, the loads recommended in my old manuals are no longer safe because IMR powders today have major different characteristics than the old powder. Anyone know if this is a valid concern, or is it just him been being overly cautious?"

It is a valid concern but not for the reason stated; the IMR powders of today are essentially the same burning rates as they were in "the old days". As it was in those old days there was some lot to lot variation but no more or less than today. Powders with different burn rates and burn characteristics are given new numbers. That's why we have a plethora of powders today along with many of the old "standards".

What is of concern is the methods of determining "maximum loads" that adhere to the relatively recent SAAMI standards. Many loads published in older manuals were developed by means other than pressure testing. Even pressure testing via the C.U.P. method is a slow tedious process and only gives a maximum peak pressure. With the advent of piezo-transducer and strain gauge measuring of pressure testing was much quicker and a more complete understanding of the internal ballistics of any load found. Additionally, while voluntary, adhering to SAAMI standards has become a necessity from the legal standpoint. With the more modern piezo-transducer and strain gauge pressure measuring it was found many of the older published loads that were assumed to be within pressure limits were, in fact, way over those limits. Especially with the adopted SAAMI standards. Many previously published maximum loads, even though thought to be safe, were found to give borderline proof level pressures.

Thus we see in many post 1980s manuals many loads with the IMR powders and others that are "reduced". The reduction had nothing to do with changes in the composition of those powders or lawyers but was simply due to the much better understanding of the actual pressures generated that piezo-transducer and strain gauge measurement along with the adherence to SAAMI standards.

Larry this has always been a concern with my 44-40 testing. My results come from only one "batch" of powder from each manufacture. Most 44-40 published data in manuals and on powder manufacture websites still uses CUP, rather than the newer (1970's) Piezo psi results. I dont know when SAAMI last tested the 44-40 in Piezo psi, but the current Piezo psi data is dated 2015.