Old vs. New Powders

M

Montana Pete

Guest
I read a posting on another shooting forum that got me thinking.

A man wrote the original post who had not followed his reloading hobby in many years, but wanted to get back into reloading.

Two issues came up-- the first one was -- old vs. new cans of the same powder.

One guy wrote in to state that standard powders change in burn characteristics over the years. So IMR 3031 from 20 years ago has probably been changed by the manufacturer and cannot any longer be counted to to be safe using old loading manuals.

I can't buy this. If the old powder has been stored in a cool, dark, dry place, I personally do not think there's a problem. As for any newly purchased container of the same powder -- the manufacturer has a benchmark for the burn rate of this powder. If any changes are made in the chemistry or manufacture, the maker will still maintain the burn rate. If not, it seems like they could be liable for lawsuits.

One way to solve this would be to load a few cartridges with an old batch of IMR 3031 and also a few with a new batch of this powder, and then chronograph the results.

Has anyone had any experience with this?

I understand numbered lots of powder can vary slightly, so a benchrest shooter who changes lots may want to use a chronograph to fine tune loads. However, I do not think the manufacturer is intentionally changing the burn characteristics -- it is just impossible to manufacture a new lot without at least some slight variation.

Another issue that came up in this thread -- the "adviser" warned against using old 1970 era reloading manuals because loads may be too hot. In truth, comparing my old reloading manuals with the new Speer #14, it appears the old Hornady manual is more conservative than the new Speer -- in other words, maximum loads are higher in the new manual.

Sometimes I use my old manuals for powders that are out of fashion, and not covered in the Speer #14. I tend to trust the old Hornady manual. Comparing, it seems more conservative toward safety than the new manual.

Well, if anyone has any comments, I'd love to read them.
 
Cannister Grade Powder

Pete:

The powders we buy for reloading all have a defining identifier (name). For example IMR 4198. These are called "Cannister Grade". These powders have to meet technical specs (including burning rate) in a very small window. Hodgdon usually makes 20,000# lots of powder. If they make a lot of H-41498 and it does not make the window it can not be sold as H-4198. It will probably be sold as "bulk" powder and used by an ammunition manufacturer to load cartridges. Knowing the actual characteristics of that lot of powder the manufacturer can adjust the charge for the load he wants.

Though Hodgdon and IMR both make a 4198 they are NOT the same powder. Generally the specs for a particular cannister powder stay the same throughout its production life. So IMR 3031 from 40 years ago should be the same as IMR 3031 produced today (within the bounds of lot to lot variations). This is the reason for the 10% low starting point when developing new loads.

As far as loading manuals compare old Speer to new Speer, and old Hornaday to new. If not it is apples to oranges. I have found older manuals (generally) to be hotter. Speer tends to be the hottest. Hornaday is in the middle. All of this is just my opinion. Others may see it differently.

Jeffrey Tooker
 
I agree that a powder company can't sell a powder and call it 4350 unless it matches (or approximates) the burn characteristics of 4350. Load books are another story however as the bullet manufacturers didn't have the level of equipment they have now. In fact, Speer, I think, used the same empirical methods, ie, bolt lift, primer appearance, etc, that the home reloader used to determine their maximum loads. Their rationale being that their methods should be consistant with their customers.
 
I've found that depending on the powder that some can vary from lot to lot enough to put a load that was a safe maximum over the top in pressure by changing lots that were made within 3 or 4 years of each other. If he has old powders and uses new data he should do what he should do in any case IMHO, reduce his starting charges by 10% from a book max and work up if possible.

Better safe than sorry.
 
An Experience

Years ago, I used to shoot large handguns quite a bit. I shot Elmer Keiths originol load of 2400 behind a 240 grn hard cast semi-watcutter in my model 29 S&W's with no ill affects.

Sometime in the 80's, 2400 got about 2 grns faster. It didn't take you long to find out if you had not bought any in years. Ever blown a primer in a S&W 44 Mag?? It ain't fun..........jackie
 
jackie schmidt said:
Years ago, I used to shoot large handguns quite a bit. I shot Elmer Keiths originol load of 2400 behind a 240 grn hard cast semi-watcutter in my model 29 S&W's with no ill affects.

Sometime in the 80's, 2400 got about 2 grns faster. It didn't take you long to find out if you had not bought any in years. Ever blown a primer in a S&W 44 Mag?? It ain't fun..........jackie
Click to expand...

Old surpluse 4831 was slightly slower then todays variety, Unique`s "new cleaner burning" version has been claimed by some to show a noticable differnce in speed also.
I`ve heard powders change usually due to the seller (Hodgdon, Accurate, ect) farming the manufacture out to differnt companies at times. I`m quite sure Hodgdon changed to ADI for some of their powder from a European source. Scott I believe bought from the lowest bidder and it`s reflected in their lables, every new lot had a different point of origin it seemed.
You can`t get real consistant product this way IMO
 
One often reads here

that the newer powders, I.E. H-4198 is a few tenths slower than the previous lot or that the 09 N-133 is slower than previous lots. In the case of 2015, the newer stuff is a lot slower than the old as H-322. My conclusion is there is no substitute for loading below what is perscribed and checking it over a crono. That way, one doesn't need to read the "Tea Leaves" of pressure build-up. You want a certain speed, you find it on the machine.
 
I enjoyed the posting from Pete Wass. The idea that a chronograph can show you a lot.

Below are two strings I fired yesterday for my chronograph. Gun was a Super Blackhawk in .44 Mag. Barrel was 7-1/2 in.

The jacketed handloads used H110. Like a lot of folks, I prefer not to put down the charge weight, since someone could blow himself up and blame me. However, these loads did not exceed the manual's maximum load. Note the difference-- I am getting about 100 fps more than the factory Winchester load.

---------------

Full handloads -- Bullet = 240 gr. Hornady jacketed, Powder: H110. Load at or near maximum in the manual. RP cases, mag primers.

1. 1502
2. 1467
3. 1466
4. 1493
5. 1461

Factory loads- Winchester -- Bullet: 240 gr. jacketed --

1. 1352
2. 1393
3. 1383
4. 1389
5. 1411

I have shot these particular handloads for years -- hundreds of them. No evident pressure problems observed. A Super Blackhawk is a very strong gun, and the .44 Mag cases are very strong cases.
 
please be-aware that the methods used for determining pressure have changed considerable over the years. The older books if you look will say cup or lup (copper or lead pellet in a fixture that bled off pressure against a piston that impacted on pellet, which was then miked for size. the size was then compared to tables for the pressure) which was the crusher method, most are now done with piezoelectric strain systems (I think that is the terminology), which are considerably more accurate. Some where in the past I remember seeing comparison tables of cup/lup/piezo.
 
Blade wrote, "be-aware that the methods used for determining pressure have changed considerable over the years. The older books if you look will say cup or lup (copper or lead pellet in a fixture that bled off pressure against a piston that impacted on pellet, which was then miked for size. the size was then compared to tables for the pressure) which was the crusher method, most are now done with piezoelectric strain systems (I think that is the terminology), which are considerably more accurate. Some where in the past I remember seeing comparison tables of cup/lup/piezo."
Click to expand...

THis is very confusing in even recently published reloading manuals such as the Speer #14.

Some cartridges set the standard with CUP, and others set the standard with "psi." The first uses a crusher, and the second method uses an electronic strain guage.

The numbers do not line up at all. A CUP pressure of 54,000 is about equivalent to a PSI pressure of 65,000.

I find this unnecessarily confusing. Why can't publishers like Speer standardize, so all cartridges are expressed by one method or the other?

Note: It is mistaken to assume that older cartridges are rated in CUP, and newer ones in PSI. If a person leafs through the Speer #14, there's not much consistency to it.

Any explanations?
 
The wide spread use of transducers like used with Oehler model 43 chronograph has caused more people to use the psi system. Really much simpler for the smaller user. The other system requires lots of other equipment and specialized barrels. With the transducer it requires a strain gauge on the outside of the barrel.

At one time there were charts available that showed a correspondence of psi to cup.

http://www.oehler-research.com/model43.html
 
In a lot of cases if there are no new powders developed FOR SALE there may not be a new manual. If there are new cartridges released FOR SALE there will likely be a new manual to follow soon. In a lot of cases a new pressure barrel is fitted for electronic data collecting as opposed to the crushers of years past. The testing of lots on a perioditic basis is quality control and is most likely internal information unless there is a recall.

Mike Swartz
 
Montana Pete said:
THis is very confusing in even recently published reloading manuals such as the Speer #14.

Some cartridges set the standard with CUP, and others set the standard with "psi." The first uses a crusher, and the second method uses an electronic strain guage.

The numbers do not line up at all. A CUP pressure of 54,000 is about equivalent to a PSI pressure of 65,000.

I find this unnecessarily confusing. Why can't publishers like Speer standardize, so all cartridges are expressed by one method or the other?

Note: It is mistaken to assume that older cartridges are rated in CUP, and newer ones in PSI. If a person leafs through the Speer #14, there's not much consistency to it.

Any explanations?
Click to expand...

It's not up to the editors of loading manuals or the people who're responsible for the data to standardize the method of pressure measurement. The Sporting Arms & Ammunition Manufacturers Institute are responsible for that in the USA and maybe Canada. There's also a European organization that does the same thing there.

Unless a person has the capability of performing the measurements himself it really doesn't matter because the manual's data isn't likely to be the same as what you'd obtain in your gun anyway. This is due to variations in the chamber, bore, rifling, powder lots, primer lots, cases, and a myriad of other variables that most people have no ability to control or even measure.
 
I find this unnecessarily confusing. Why can't publishers like Speer standardize, so all cartridges are expressed by one method or the other?

Note: It is mistaken to assume that older cartridges are rated in CUP, and newer ones in PSI. If a person leafs through the Speer #14, there's not much consistency to it.

Any explanations?
Click to expand...

I believe the manuals such as Speer (Lyman and a couple others are also now showing both types of pressures) which are showing both CUP and Piezo pressure values are in fact moving to the piezo method, but haven`t reshot all their data. There is no good formula for converting one to the other so every CUP load has to be reshot for true pressures in PSI.
The formula Denton wrote given in the link above is only a close approximation and then only good within a certain pressure window. It gets you and I close when we want to convert one to the other, but in a reloading manual, close don`t count.
 
You can't depend on any formula for converting CUP to PSI because the difference in the readings is in part due to the effect of the shape of the cartridge case of the ammunition tested.
The .30 Carbine straight tapered case gives near identical readings in both CUP and piezo PSI, while other case shapes give a much greater spresd between CUP Values and PSI.

Powders do change in burning rate after many years of storage, some double base powders change very little while some single base change quite a bit according to how well they were stored.

The story on Hodgdon H4895 for example is that Hodgdon sent samples of his remaining stock of Military Surplus IMR4895 to a company in Scotland for analysis so a new powder with identical properties could be formulated. The samples had degraded slightly in storage so the new powder ended up as a duplicate of slightly degraded IMR4895 rather than duplicating freshly manufactured 4895. Manufacture then shifted to ADI in Australia where new manufacturing techniques gave the H4895 superior temperature resistance and stability, though the chemical ingrediants were the same.

A man wrote the original post who had not followed his reloading hobby in many years, but wanted to get back into reloading.
Click to expand...
Same here, plus I now have a couple of antiques that I'll need to baby, plus factory ammo for some older rifle chamberings is hard to find around here and pricey.

Recent developments in IMR and ADI powders show some real promise. Earlier on you'd have to allow for higher pressures in equivalent balistic loadings when single base propellants were used with some older cartridges that were designed around low intensity double base powders. Now some single base powders like IMR 4007 SSC can match those energies and velocities at the same or even significantly lower pressures.
 
You must log in or register to reply here.
Back
Top