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Old May 20, 2006, 01:19 PM   #1
sterno
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Single vs. Double based powders

What the real difference between single and double based powders? Someone told me that single based powders are corrosive. Is that true? Does one burn cleaner then the other?
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Old May 20, 2006, 01:46 PM   #2
918v
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Bouble-based powders contain nitroglycerine, and offer slightly higher velocities at the same pressure level.

I use whatever gives me 100% load density and 100% combustion. That could involve either a single or double base application. 100 FPS is not enough to stress over.
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Old May 20, 2006, 01:51 PM   #3
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The down side of the double based powders is usually a higher flame temperature. This can accelerate wear in high pressure loadings.
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Old May 20, 2006, 01:58 PM   #4
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But that is kept in check with coatings, so throat erosion is actually similar.
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Old May 20, 2006, 10:15 PM   #5
HSMITH
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I feel that the whole debate about single vs double base = blah blah blahblah blah blah.

What works? What is consistent over the chronograph? What is more accurate? What meets YOUR needs?

Those are the important questions to ask when selecting a powder. Your question has merit from an academic point of view, but little practical application.
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Old May 21, 2006, 08:18 AM   #6
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I'm actually glad there isn't much difference between them.

I got the info about them being so different from a guy who's been reloading the same way, with the same components, for 20 years. His info seemed 20 years old as well.
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Old May 21, 2006, 08:30 AM   #7
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Sterno:

Good answers so far ... and, no, single base powders are not corrosive. Neither are double base powders. And I don't know of any smokeless powders that were ever truly "corrosive" ... I believe the primers were always the issue.

In general and in THEORY, single base powders burn cleaner and double base powders are less sensitive to temperature variations. But given the variations in grain size and shape, along with formulation and coating differences, you really can't make any realistic wholesale claims of one vs. the other.

(not to metnion that powders burn radically different based on application, and we certainly have different ideas on what "clean" is ...)

I'll go with HSMITH on this one ... blah blah blah

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Old May 21, 2006, 08:40 AM   #8
sterno
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Why is that info so hard to find in a written text?

The guy who told me all that nonsense told me that single based powders were corrosive and that double based was cleaner.

Like I said, 20 year old info...and bad info at that. He also hasn't changed his reloading recipie for 20 years, even with the advent of all those newer powders. I understand that you keep what works, but come on! After that long you'd think you'd at least want to give modern science a shot! (no pun intended)
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Old May 21, 2006, 11:21 AM   #9
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Get Quickload and let the program guide your powder selection.
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Old May 21, 2006, 11:49 AM   #10
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Corrosive is the wrong word.

Errosive would be the correct word, due to higher flame temperatures.

However, that's pretty much a thing of the past due in large part to the aforementioned powder coatings, but also better steels.

Old British cordite was well known for its extremely high flame temperatures and its ability to eat the throats and rifling leads out of early Lee rifles.

In fact, the rifling change from the shallow Metford type to traditional deep cut rifling around 1895 was done specifically for that reason.

It's still not uncommon to find early, unrefurbished Lee-Enfield rifles with bad throats and washed rifling.
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Old May 21, 2006, 07:28 PM   #11
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you can find some info out in arguments of Vv N320 vs Hodgdon Titegroup among 40sw loaders that shoot competively.

Titegroup is a double with Nitro and supposedly can make a barrel hot easily. you may hear some folks complain about titegroup making barrel hot as we get into summer with warmer temps.
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Old May 21, 2006, 10:36 PM   #12
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TiteGroup puts more heat into the gun and does it faster than anything I have EVER loaded before. It is also temperature sensitive and position sensitive. I HATE it!!! I burned a couple pounds in competition 40 loads and really don't have anything good to say about TiteGroup.

Universal and regular Clays are double, from the same company, and don't put anywhere near the heat in the gun. They are also less position sensitive and about equal on temperature sensitivity.

Each powder is an individual powder, and should be looked at that way. Drawing assumptions without the testing won't do any good. Load, shoot, chrono, heat, cool, test the loads or you just won't know what you have.
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Old May 23, 2006, 12:22 AM   #13
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see what I mean

easy HSMITH dont blow a gasket.

last I looked the Clays products are from Australia and Titegroup is made in the USA.
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Old May 24, 2006, 01:32 AM   #14
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Smokeless powders are not corrosive but the original "WA" powder used for 30-03 and 30-06 loads was 30% nitroglycerin and might as well have been corrosive. There were reports of barrels were burning out after as few as 800 rounds. It's documented somewhere in one of Sharpe's books. In moving away from this formulation and studying what the Germans were doing with their powders led to the creation of the Improved Military Rifle series of smokeless powders.

If you want to know more about powder and primers get Philip Sharpe's Complete Guide to Handloading It was first published in 1937, and contains an excellent history of the development of primers, black powder, smokeless powder and reloading gear.
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Old May 24, 2006, 10:16 AM   #15
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DJL,

As I noted above, the powder wasn't corrosive, it was errosive. The high flame temperature and the soft steels available in the 1890s led Winchester to discover the same thing that the British did with their cordite of the same time -- either tame the flame temperature by reformulating the powder, take other measures, or expect bad barrel life.

But, given that primers of the time were still corrosive due to the potassium salts, it's also possible that people bought into the old advertising, that the new smokeless powders didn't harm your gun like black powder, a little too much and slacked off on their cleaning regimes, which certainly would not have helped the situation at all.
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Old May 26, 2006, 09:43 PM   #16
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Single base, double base, chocolate, vanilla, its whatever works in the recipe you're making.
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