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Discussion Starter #1
I am relatively new to the details of Hand Loading and have found little in explanations about the variation in burn rate of a given powder with the pressure at which it is burned.
Intuitively, I think that the 'burn rate of a powder would be affected by many things such as it's chemical composition, the form or geometry of the powder, the size of the powder grain, any surface treatments, Combustion Pressure among others.
I also believe a plot of the burn rate vs time vs combustion pressure would be useful in selecting powders for applications but I have found only "Relative burn rate tables" which do not indicate the conditions under which the selections were made in order of listing.

Has there been any research into this?

Are there published data or diagrams of the characteristics?

Is this even Germain to Hand Loading load development?

Best Regards,
Chev. William
 

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Discussion Starter #5 (Edited)
Thank you for the three references.
The first would not load on my computer beyond page 14.
The second startled me with the $115 dollar price if i wanted to read the page cited.
The third, I gave up on after 10 minutes waiting for the first page to appear while it was still loading.
I may need to look for another computer to look at them on.
 

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Intuitively, I think that the 'burn rate of a powder would be affected by many things such as it's chemical composition, the form or geometry of the powder, the size of the powder grain, any surface treatments, Combustion Pressure among others.
True. Nitrocellulose (energy component of single-base powder) burns at a rate of a certain number of inches per second at any given pressure. That rate increases as pressure increases, which is why it takes a very long time to burn, for example, 47 grains of 4350 when it's in a pile on the ground vs. how quickly it burns in a 30-06 case in a rifle. Deterrent compounds alter burn characteristics, as does adding nitroglycerine (double-base powders) and then nitroguanadine (triple-base powders), and of course perforations alter surface area in a powder granule (both initially and as the granule burns), thus making a perforated granule burn differently than a non-perforated granule.

I also believe a plot of the burn rate vs time vs combustion pressure would be useful in selecting powders for applications but I have found only "Relative burn rate tables" which do not indicate the conditions under which the selections were made in order of listing.

Has there been any research into this?

Are there published data or diagrams of the characteristics?

Is this even Germain to Hand Loading load development?

Best Regards,
Chev. William
Information of that general sort may play a part in how the powder suppliers we generally know of (Hodgdon, Alliant, Accurate, etc.) 'select' the powders they purchase for re-sale to consumers from the actual powder manufacturers (General Dynamics, Thales, Eurenco/Groupe SNPE, Rheinmetall, etc.).

For us as casual handloaders, such information may be highly interesting and educational, but I think that the 'service' or 'value' provided by the powder companies whose names are on the powder containers we buy, is taking that information into account and selecting good options with which to develop handloading data.
 

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Thank you for the three references.
The first would not load on my computer beyond page 14.
The second startled me with the $115 dollar price if i wanted to read the page cited.
The third, I gave up on after 10 minutes waiting fo rth efirst page to appear while it was still loading.
I may need to look for another computer to look at them on.
Five seconds or less for me! :confused:
 

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The easiest way to see how different powders behave is to compare the recipes in a loading manual to different cartridge shapes, what gives the highest velocity in a smaller cartridge won't be the same in a larger cartridge, that is why burning rates are not constant, in fact some powders will behave like a much slower number in certain cartridges than what you would expect. A good example of this is in the 338WM, RE19 behaves slower than RE22 and gives higher velocities with the same pressure. RE22 behaves like a faster powder for some reason in the 338WM, which has me baffled, but is a fact.
It's also noted that straight wall, or almost straight walled cartridges tend to slow medium burning powders down to what you would expect from slower numbers.
My 375 Weatherby is a very good example of this, even though it has a larger capacity than my 300WM, which gets it's best results with RE25, the 375 gets it's best results with W760, RE15 and H4350.

It's a very interesting element of powder behaviour, in the early days of my reloading I never understood this fact, but now knowing these characteristics, I can load for the most efficient load AND get the highest velocity for a given powder charge. A chronigraph really helps with this no end, I must add.
Hope this explains it adequately.
Cheers.
 

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Try the product called QuickLOAD. It allows you to look at powder characteristics and even modify them. Its a really fun simulator and very useful to the handloader - I use it all the time. -Art
 

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Chev......I think you have a good question. I am no Master reloader, chemical engineer, or mathmatician, I do like the Burn Rate Chart for some things, but IMHO, I take it at face value. I am sure somewhere there are extrapolated tables taking all of the powders out to basic compositions. The chart is a tool in your reloading box, and should be for what you need to do, your very best reloading. A 516 page volume taking powder down to the basic elements is not really needed for the average reloader.

It is like, not having to be an automotive engineer to know how to drive or work on your car, although it may seem like it with the new cars. You don't have to have a schematic of all the printed circuit boards to operate a PC.......the complete volume(s) of basic powder characterists is just way over kill, for all but a small percentage of reloaders! But I would suppose that if you knew all of that information that you would indeed sound like you had spent the night in a Hoiliday Inn!
 

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Information of that general sort may play a part in how the powder suppliers we generally know of (Hodgdon, Alliant, Accurate, etc.) 'select' the powders they purchase for re-sale to consumers from the actual powder manufacturers (General Dynamics, Thales, Eurenco/Groupe SNPE, Rheinmetall, etc.).

For us as casual handloaders, such information may be highly interesting and educational, but I think that the 'service' or 'value' provided by the powder companies whose names are on the powder containers we buy, is taking that information into account and selecting good options with which to develop handloading data.
Well said!

In loading for M1 Garrands the pressure curve of the powder must be correct for the gun to function properly. Most all of us do not have the equipment needed for this kind of testing and powder evaluation. I rely on the information and ground work done by the manufacturers and always check at least 3 reliable sources before handloading anything. Also any change whatsoever in components, lot #s, etc. needs to be approached with caution. Reduce powder charges by 10% with any change.

Even when loading for wildcats I check relative burn rates and correspond with the manufacturers for guidance. Most are willing to help, some, no so much.

Let the pros do their part and enjoy handloading
 

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Your concern about powder burn characteristics is well-founded. The major early problem with the M16 in Vietnam was "failure to extract", caused mainly by the fact that the powder used in the issue 223 (5.56) cartridges was changed at the last moment. The new powder (a "Ball" design) was a bit slower than the development powder. While it had about the same chamber pressure and Muzzle Velocity as the original, it had higher port pressure, resulting in a higher cycling rate. The higher bolt acceleration made it more difficult for the extractor claw to grip and extract the fired case, especially from a dirty chamber. The problem was compounded by the fact that the early issue M16s did not come with a cleaning kit and rod, so it could be impossible to remove the stuck case without tailoring some long twig to serve as a rod. Meanwhile, you were prrobably dead.
A nice thing about QL is that it gives you a pressure curve that you can compare with other powders. -Art
 

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The easiest way to see how different powders behave is to compare the recipes in a loading manual to different cartridge shapes, what gives the highest velocity in a smaller cartridge won't be the same in a larger cartridge, that is why burning rates are not constant, in fact some powders will behave like a much slower number in certain cartridges than what you would expect. A good example of this is in the 338WM, RE19 behaves slower than RE22 and gives higher velocities with the same pressure. RE22 behaves like a faster powder for some reason in the 338WM, which has me baffled, but is a fact.

Cheers.
I agree that studying load manuals is educational but you have to understand much if
their data has great margins of error and can only be trusted so far. Especially where
many of the powder mfgrs no longer supply pressure info with the load tables.
In your case with the 338 WM, we are not getting the truthful whole story and I would
not consider burn rate anomalies due to the inconsistency of their data.

I no longer try to explain anomalies ( unless I witness them ) .... .Instead, I doubt them

Consider Alliants recent published data for 338 WM:

REL 19 200gr bullet 76gr 2806 fps
REL 19 225gr bullet 78gr 2944 fps
REL 19 250gr bullet 72gr 2664 fps

REL 22 250gr bullet 73 gr 2653 fps

I guarantee there is error with the 200 and 225 gr data and so I have to throw
the whole lot out with the REL 19 info.

Although they have not shown you the numbers, it is very possible that REL 17 would
outperform REL 19 and REL 22 despite all logic as the REL 17 is a completely different
technology powder from a different supplier. In several other calibers their load data
illustrates this fact. Very weird to me but I can only rationalize that REL 17 has a
great deal more energy ( nitro content?)

That said, I do believe some powders change in relative burn rate ranking based
on pressures. This would occur in an instance where you used a powder in a magnum
type cartridge at plus 60K psi and then loaded another cartridge for instance in the
mid 30Ks or 40Ks psi. THIS is what we need the powder mfgrs to tell us... other than
as hidden data in their load manuals.
 

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Discussion Starter #17
Try the product called QuickLOAD. It allows you to look at powder characteristics and even modify them. Its a really fun simulator and very useful to the handloader - I use it all the time. -Art
I now own a Registered Copy of "Quick Load" software and have it installed in my computer.
I am still learning it's 'ins and outs' and from what I have seen so far it is going to be a long time before I understand and can properly use all it's functions and options.

Thank you for the hint.

Best Regards,
Chev. William
 

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Discussion Starter #18 (Edited)
The following is copied from another thread on Another Forum as it makes my understanding of these two propellants performance Better.
"ammoguide
Occupied Zone, CA
Posts: 1810
Joined: 11/29/03
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01/24/18 12:18 EST
CW, as a result of your post, I decided to find the warning on the Hodgdon website and perhaps a better explanation. To my surprise, I could not find it anywhere. So I sent the following query to Hodgdon and received the following reply:
Hodgdon used to warn against reducing charges with H110 powder more than 3% below maximum. The specific warning was: "H110 Loads should not be reduced more than 3%. Reduce H110 Loads 3% and work up from there. If reduced too much, H110 will cause inconsistent ignition. In some cases it will lodge a bullet in the barrel, causing a hazardous situation (Barrel Obstruction). This may cause severe personal injury or death. DO NOT REDUCE H110 LOADS BY MORE THAN 3%."

I just searched Hodgdon.com and I can't find this warning anywhere. Is this no longer a consideration? If not, when and why did it change? You see, as the owner of AmmoGuide is now... "Interactive"! I post this warning anytime listed loads include H110. If it's no longer applicable, I'd like to stop displaying the warning and understand why not so I can explain it to my 50,000+ members.

(Hodgdon replied)
We certainly did warn of reducing H110 max loads by more than 3% in the past. I have looked through the latest publications and have found that you are absolutely correct, the 3% warning is gone.

The nature of this warning is actually exactly the opposite of what most shooters/reloaders think. You will never get into high pressure problems by reducing the H110 loads more than 3% but, H110 is a true magnum powder. It wants magnum primers, heavy bullets, heavy crimps and heavy charge weights and proper pressures within the case to work properly. When H110 is reduced too much (as in more than 3%) below the listed Max load (unless the starting load is tested in the lab and shown) the pressure drops off exponentially causing a low pressure environment in the case. Without proper pressure, the flame will not be able to support the combustion of the magnum powder and the powder charge will quit burning leaving a bullet lodged in the barrel and a great deal of unburned powder.

So, I will check in with the man in charge of our manuals to bring this to his attention when he returns from the SHOT Show next week. Thank you for pointing this out to us.
(Ammoguide continues)
Of course, since W296 is known to be the same powder, I include it in my warning about using these powders.

So, there you have it, "right from the Hodgdon's mouth." To answer your original question, if your posted Hornady data is correct, they are violating Hodgdon's long-standing safety policy about using H110/W296 and I bet they would appreciate hearing about it. Since I do not have the Hornady manual in question, will you please tell them about it?

-- Post last edited 01/24/18 12:25 EST

chevwilliam
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01/24/18 22:30 EST
Mike, thanks for posting the Updated Explanation on H110/W296 Powders relating to reduced Starting charge weights below the listed Maximums.

This makes many .30 Carbine posted loads more understandable, the ones with stated Starting charges more than 3 percent less than the maximum listed, and those with less than 97 percent fill.

Best Regards,
Chev. William"
 

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If you are interested in general info or ideas about things, then QL is a neat little calculator. If you are looking for "answers" and study, then be very cautious about relying upon QuickLoad.

There are a growing number of newer powders and especially progressive powders out there, that QuickLoad simply doesn't accurately describe at all. If you go over any of my posts about testing and pressures, most of them show examples of these. Progressives can radically change their burning speed, and thus change the pressure curve substantially. Also when you get a notably different bullet construction such as the Traces with the Deep curl and 748, you can make "normal" powders get cranky and begin to run away rather quickly.

For true study and answers to what is happening in your particular rifle, with your particular components, you need to measure pressure; not calculate it. The most affordable system I know of, is the RSI Pressure Trace II system.

Cheers
 
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You can stare at a computer screen until your blind trying to figure out what all the data means but it's no substitution for shooting your gun with your ammunition over a chronograph and measuring your cases with a micrometer.
IMO there are to many variables to draw conclusions from other peoples data.
 
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