Actual Smokeless Burn Rates in Feet per Second?

[MUSTANG]

I was contemplating on powder this morning and the numerous posts seeking to find a replacement powder for their favorite XYZ powder and application. My personal powder vault has listings with some 30 years old, and some that are recent new listings by Hogdon/IMR/etc..


1. Are burn rates for Powders actually available somewhere?
2. Would burn rates for Powders (ranges in FPS) be beneficial to readers of this forum?


When attempting to develop new loads, we seem to use 100 plus years of "one to one comparison" between powders to create tables. We have multiple Tables available on this forum and other sources where various powders are rated in a numeric scale of 1 to hundreds based on "Relative" burn rates, such as this extracted table:



1
R-1, Norma


2
Nitro 100, Accurate


3
N310, Vihtavuori


4
Titewad, Hodgdon


5
Bullseye, Alliant


6
BA 10, Vectan


7
WST, Winchester


8
Red Diamond, Scot


9
P805, RWS


10
N312, Vihtavuori


11
Clays, Hodgdon


12
W-230, Winchester


13
Red Dot, Alliant


14
e3, Alliant


15
Promo, Alliant


16
Solo 1000, Accurate


17
Solo 1000, Scot


18
AA Plus, Winchester


19
Titegroup, Hodgdon


20
N318, Vihtavuori


21 etc......


We have other tables where powders are listed in multiple columns, with powders having similar burn rates are listed on the same line of the columns for comparison purposes.

125555


This line of thought got me to wondering why we do not see Smokeless Powders listed in their burn rates in Feet Per Second?

Dipping back into my military days, we used to have some simple tables for the "Burn Rate" of various explosives in feet per second. The classic example would be "Det Cord" (Detonation Cord) which when laid out in a many hundreds to thousands of feet can literally be seen from a distance to "Burn" (explode) in a linear fashion at a specific rate. The following are ranges or specific burn rates for various explosive compounds in "Feet Per Second".




Lead Azide
13,400 to 17,000 feet per second


Lead Styphnate
17,100 Feet per second


Mercury Fulminate
11,500 to 21,100 feet per second


Tetracene
Less than 13,100 feet per second


Amatol
14,800 to 21,100 feet per second


Ammonal
17,700 feet per second


Ammonium Nitrate
3,300 to 8,200 feet per second


Ammonium Picrate
22,500 feet per second


Astrolite
2,600 to 26, 200 feet per second


C-4
26,400 feet per second


Cyclotol
25,900 to 26,400 feet per second


Flex-x
22,300 feet per second


HBX (Torpex)
22,700 to 23,700 feet per second


HMX
29,900 feet per second


Kinepak
20,100 feet per second


Minol
19,100 to 19,700 feet per second


Nitro-Cellulose
21,900 feet per second


Nitro-Glycerin
4,900 to 25,400 feet per second


Nitro-guanidine
25,100 feet per second


Nitro-starch
16,00 feet per second


Octol
27,500 to 28,300 feet per second


Pentolite
24,500 feet per second


PETN
27,200 feet per second


Picratol
22,900 feet per second


Picric acid
19,00 feet per second


RDX
26,800 feet per second


Tetryl
25,800 feet per second


Tetrytol
24,000 to 24,200 feet per second


TNT
21,800 to 22,400 feet per second


Torpex
24,600 feet per second


Tritonal
21,200 to 22,000 feet per second




Food for thought and discussion.

[35remington]

Since you can use neither burning rate charts nor charts that show burning rates in feet per second as loading data, who really cares?

I suspect that a great many powders would overlap. Little useful information would be obtained as again, it's not loading data. That's what we're after, and yes, many powders don't have loading data. A burn rate is a poor substitute.

[dragon813gt]

FPS is only good for that cartridge w/ that bullet at that COL in that length barrel in that firearm. It's of no use. Burn rate charts are in relation to each other so be cautious when using them.

[sdcitizen]

What would be neat is to see a time-pressure curve for powders, it would give an indication of usefulness for reduced pressure loads.

[btroj]

Since all of this is relative to the exact load/firearm combination being used none of it really matters.
A relative burn rate chart is handy to see what powders are similar to each other and nothing more.

[MUSTANG]

What would be neat is to see a time-pressure curve for powders, it would give an indication of usefulness for reduced pressure loads.


This is somewhat the thrust of "Why". We know that using say a very Slow 50BMG/Vulcan 20mm Powder is going to give us a slow burn rate that should have a flatter curve and pressure wave in the barrel; but that's inductive reasoning that gets us there not specific data. As my casting/reloading gets into the several decades, I am becoming more interested in the Internal ballistics. Do not have the measuring capabilities of a Powder manufacturer, nor even someone like Larry Gibson who has shared a lot of Trace Graphs concerning pressure curves in many of his posts.

To the issue of not having all of the data for "FPS is only good for that cartridge w/ that bullet at that COL in that length barrel in that firearm." ; that is exactly the point. Once we depart from the exact mold made by a specific manufacturer, sized as they state, using their Pressure Barrel, of a specific length, and a specific powder, with as specific charge - we are on our own. The further we digress from that specified & specific published data, the more we are in uncharted territory. If we buy a "New Design" mold from a group buy; we are extrapolating data to set hopefully a safe path to developing a useable and safe laod with that new variable.

As an analogy back to my military days and explosives, we might take those limited tables of explosive and their burn rates and apply them (Was not an engineer, and the truth is that often getting an engineer to support small actions was not viable from time/logistics/availability). Yet, we could decide if we wnated to "Push" and object with explosives (slow burn rates), cut an object (shape charges & wrapped with medium burn rates), or fracture (medium to fast burn rates). Same logic went into weapon systems selection to engage a target (be it Naval Gunfire, Mortar/Artillery, or Air Delivered).

I was just thinking that a "Quantifiable Number/Range" for burn rate would be interesting, and perhaps useful. Currently if we step outside of the range of using a published recipe, we rely more on Inductive reasoning based on Printed Load Data, or experience of those who share their years of collected knowledge and personal experimentation. Quantifiable numbers are more limited in some aspects.

[btroj]

Wth the number of variables involved it would be very difficult to quantify burn rate.

Some me powders change places on the charts in some applications. Guns have so many potential tolerances that they are all individuals.

Are we flying by the seat of our pants? A bit, yes. This is why we study manuals, watch for signs of trouble, and make good observations.

[dragon813gt]

We really aren't flying by the seat of our pants w/ programs like Quickload. It does a great job if keeping our loads in the safe range as long as you enter all the variables correctly.

To try and pin a powder to a quantifiable number is an impossibility. There are to many variables. Throw temperature and position sensitive powders into this discussion and you see how it just can't happen.

[stephen m weiss]

I think it is a good question. I worked up a spreadsheet to do internal ballistics and I use it for all my loads. The basic formulations as described in quickload work quite well, and by doing a 30% 60% 90% 100% load with the powder packed with filler, fiddling values till errors are small, I got very consistent and predictive results for my powders. The results for burn rate and pressure exponent are pretty consistent between 223 and 308 and 7.62x39 cartridges.

The next issue is determining the time constant for a grain burning is determining whether convection or conduction is limiting the heating of the powder. I think for very small grains, convection is limiting it, so it is the surface area to volume ratio that controls the heating. Since the surface burns away, the grain gets faster and faster the smaller it gets, which is why it burns out rather that burning for ever.

The trick is converting the fuse burn speed to grain burn time and pressure exponent(typically 1), so really just grain burn time. An estimation and check with several different powders vs their physical size should solve the matter quickly.

I find the burn rate in fps very interesting. My question would be what is the definition of this? Is this literally the burn rate of a typical solid fuse of the stuff? So, you could extrapolate the burn time for a powder based on its composition and grain size.

This leads into what I have been wanting from people when they talk about their powder: just give me the physical dimensions of the grains. The dimensions are much more important than the name or purpose of the powder. The chart above shows only mild changes are due to powder composition, 13kfps to 21kfps.

So nice to see someone trying to understand more instead of buy more. Every purchase puts tax dollars into a bloated government so that it can afford to write and enforce laws faster to remove our rights. Sadly, it's that simple.

[dragon813gt]

H110 is a very fine ball powder and it burns slower than HP-38 which is physically a lot larger. I can't possibly begin to discuss smokeless powders as I'm not a chemist. But there is a lot more to the burn rate then the physical size of the grain.

[btroj]

Our powder isn't burning in a linear fashion like det cord. We have volume to take into account not to mention the shape of the containment vessel.

Quickload is a pretty dang close judge. I wouldn't go straight to max loads based on Quickload but it gives a pretty good idea where you are.

[shooting on a shoestring]

Mustang, thanks for putting some thoughts out there. That's an invitation to criticism for sure. Thinking outside the box is not for the thin skinned.

I notice your military explosives burn rates make the assumption the explosion burns in ambient pressure. Problem with contained charges of smokeless propellant is that the containment varies the burn rate. And worse yet, two powders that have very close burn rates in one containment can have very different burn rates in a different containment.

A burn rate chart or ranking in ambient conditions would not be useful for comparing the same powders under containment. And as soon as you define the containment, like the shape of it, the amount of free space, how easily or how hard the containment walls can move, how quickly the volume of the containment can change, then you have a burn rate chart for that specific set of variables. Change a variable and the rankings will also move around, but not so predictably as we would like.

Nice thought and it would be nice if powders were that predictable. They just don't behave that well.

[btroj]

It would be AWESOME if it was that simple. Damn laws of physics just won't allow it.

I blame Newton, it is all his fault.

[stephen m weiss]

Hmm. worked pretty well for me. perhaps you have to take a serious whack at it. Try getting a heat transfer textbook. Amazon sells them.

Thx for the cord burn rate chart. I copied it and will see how it matches with grain burn rates.

[shooting on a shoestring]

Stephen, nice work.

Yes you can dig deeper into burn rates, heat transfer in static conditions, heat transfer in compressed materials, combustion kinetics and even quantify how the friction coefficient changes as the boolit moves from stationary and into the case mouth, throat and engages rifling.

If you're good at it by all means do it! If you enjoy it, I hope you have great success.

What I see is a burn rate chart gives me a way to categorize powders. It's something to use to describe an unknown powder as say fast like Bullseye or maybe it's slower than 4831.

To to get around all the science of predicting precisely how a powder will behave, I start low and work up for my particular load combination. I think I'd still do that if I had a published spreadsheet accounting for all the variables.

I'm not saying don't work on it, please do. I'm just saying I'd rather shoot. Working on a spreadsheet that would make as good of predictions or better than QuickLoads seems like a lot of work with a small payoff. I like my hobby to be fun, not work. Therefore, I'm an experimentalist and not an engineer.

[MUSTANG]

Hmm. worked pretty well for me. perhaps you have to take a serious whack at it. Try getting a heat transfer textbook. Amazon sells them.

Thx for the cord burn rate chart. I copied it and will see how it matches with grain burn rates.

stephen m weiss:

Please keep us posted on your efforts. I would be interested in seeing the progress your explorative and recorded efforts. Keep in mind the explosive burn rate table I provided above lists numerous chemical compounds (explosives) and each has it's own burn rates. Detonation cord being only one designed product that contains a specific explosive (PETN), other uses are for detonators, shattering items, etc..

I suppose the root of my original contemplation was that within the range of explosives there were "Ranges/Rates of Burning" for the wide variety of explosives. These same ranges of explosives are placed into a range of different packages, and made into different shapes (i.e wide variety of shape charges) to accomplish specific actions.

There is a considerable range of permutations that occur for the design of these explosive compounds/packages/shapes; with the burn rate/range being a considerable planning factor. For smokeless powder the same must apply, we know that the same effort goes into development and production for rifle/pistol/shotgun powders. My observations is that over the last ten to fifteen years we have seen significant effort by smokeless powder manufacturers in their powder efforts. We have seen additional development in powder grain shape (as an example the expanding "Short Cut" offerings), coatings (military efforts to provide reduced flash signatures and less temperature sensitivity for rifle and pistol loads), and in other areas I am sure. Just seems that the "Burn Rate" has to be a critical part of each of those efforts - a foundation of the "Science" to achieve a specific result rather than some voodoo closet chemistry, yet we in the shooting and reloading community remain uneducated in these basis other than the use of tables just as we have been doing for more than a hundred years.

[John Boy]

Mustang, the table with the compounds in "Feet Per Second" is informative and educational. Primer powders are a mixture of several of the compounds listed, primarily Lead Styphnate and no 2 brands are the same combination of compounds for pistol & rifle primers. All primers generate a briance, slow or fast feet per second, to ignite the powder charge. Different briances for smokeless & black powder powder charges effect accuracy shooting long range, especially for BP that deflagurates the powder charge v smokeless that explodes the powder charge
Thanks for posting - I copied the chart to my references

[Idz]

There seems to be some confusion here. The table is listing explosives detonation velocity. Explosives detonate supersonically, meaning the unexploded material knows nothing about the explosion pressures and temperatures until it begins exploding. Propellents like gunpowder are actually burning. The propellent burn rate depends on the local temperature, pressure, and surface area so is constantly changing as the powder burns and accelerates the projectile.

[fouronesix]

There seems to be some confusion here. The table is listing explosives detonation velocity. Explosives detonate supersonically, meaning the unexploded material knows nothing about the explosion pressures and temperatures until it begins exploding. Propellents like gunpowder are actually burning. The propellent burn rate depends on the local temperature, pressure, and surface area so is constantly changing as the powder burns and accelerates the projectile.

I'd say so! Well put. I too have no clue how feet/second burn rates apply to confined smokeless powder burning in a non-static, dynamic system (like a firearm). IMO- it simply doesn't nor can't apply and much of the discussion is without basis, or is at best, purely academic.

[wiljen]

Mustang, if you haven't seen this artricle already, you might want to check it out.

http://www.dtic.mil/cgi-bin/GetTRDoc%3FAD%3Dada261009&ei=XFSpVJDqMYy0ggT-mID4Dw&usg=AFQjCNGjfFxCtWxsIdwdIHFT-AenUU7qEg&sig2=DbmiaEZEBd-izAnoEeRI8w&bvm=bv.82001339,d.eX%5CY

[MT Gianni]

Over 35 years ago my trainer in the Gas Business said it best. " You cain't outrun flames".