Powder Burn Rate Chart?

[W.R.Buchanan]

Everybody has a Powder Burn Rate Chart showing fastest to slowest powders. I've got several.

However this only tells part of the story. All Explosive Combustion Speeds are rated in Feet Per Second. IE: C4 is around 32,000 fps. The faster it burns the bigger the pop and the more powerful/effective it is..

Gun powder is rated the same way except we never see those numbers.

Point being, there could be a big jump in speed between two powders that are right next to each other, and then a small jump to the next powder. Powders like H110 and W296 and several others are exactly the same but don't occupy the same line in the chart. One is above the other and I have even seen several others in between.

By knowing these numbers we could pick powders more accurately, and obtain better results.

Does anyone here have a Burn Rate Chart that gives the FPS of each powder's speed of burn?

Randy

[megasupermagnum]

Are you sure smokeless powders are rated the same way? They are not explosives. Very rarely do burn rate charts agree with each other. Some powders, Longshot for example, can be shown all over the map from nearly by 2400, to almost as fast as Unique.

[tomme boy]

A lot depends on the expansion chamber the powders are burning in. Some powders behave normal in certain cartridges then get scary in others. I have had more problems with ball powders than any other type. So I don't think there is any type of list like you want. Or one available to us.

I have had good luck calling Hodgdon and asking ?'s. They have kept me on the line for over an hour telling me all about a SEE and why it does not happen in a firearm. Then to tell me another name for it that pretty much says the same thing the way they want it called.

The other guy is at Shooters world powder. His name is Ken Johnson. He really knows his powders. I have his private email but will not post it here. If you want it, message me.

[longbow]

Not sure you are quite correct there Randy. Gunpowder burns and in deflagration, high explosives like C4 detonate.

What is the difference between a deflagration and a detonation?

Combustion (burning) is a process by which energy is released. ... If the combustion process propagates outward at subsonic speeds (slower than the speed of sound), it's a deflagration. If the explosion moves outward at supersonic speeds (faster than the speed of sound), it's a detonation

Or from ThoughtCo.:

https://www.thoughtco.com/explosions...onation-607316

and from NRA:

https://www.nrafamily.org/articles/2...s-of-gunpowder

Also, what is said above. The rate of deflagration of smokeless powder depends on type of containment and pressure so burn rate for same powder can differ. As in long skinny cartridge versus short fat cartridge. I know... there are burn rate charts but if there isn't enough pressure the powder does not ignite properly nor does it burn completely. Maybe as a generality smokeless powders behave the same in any given shaped chamber so are comparable that way. Not sure. Maybe a good question to ask.

Longbow

[W.R.Buchanan]

Mega: they still have a burn rate in FPS. It is nowhere near to the speeds some explosives operate at but it is still there or they couldn't rate a speed.

Speed is Time x Distance. IE; Miles per hour, Feet per second etc.

Randy

[longbow]

Well, I get a little lost in this pretty quickly but my previous understanding was that smokeless powders are at least somewhat pressure dependent for burn rate so open air testing of a "trail" of powder is not applicable.

What I am finding on this search is that testing is typically done in close chamber high pressure environment and the impression I am getting is that the measurement is a volume or mass consumption rate that varies with pressure. Not sure as I haven't read it all and don't plan to do more than skim through it but I suspect that smokeless powders are rated based on a certain chamber size and pressure for comparison. It seems that "standards" are industry controlled... I think.

Some links for the mathematicians in the group:

https://dspace.lib.cranfield.ac.uk/b...=1&isAllowed=y
https://www.researchgate.net/publica...Gun_Propellant
https://apps.dtic.mil/dtic/tr/fulltext/u2/a043778.pdf
https://pubs.acs.org/doi/abs/10.1021/ac60009a004
https://apps.dtic.mil/dtic/tr/fulltext/u2/a043778.pdf

Interesting question though and as I am sure most are aware is that burn rate charts are simply comparisons of where powders sit relative to one another, not the gap that is between them.

A somewhat confused...
Longbow

[vagrantviking]

Each lot of powder, even with the same designation, will have different results.
How different? I have no idea. It might be enough to change the order on a chart compared to the variation of the others that are just above or below.

[BJK]

It's easy enough to find how fast it burns without pressure just lay some out in a line and touch a match to it. It's pretty slow until it's under pressure. Contrast that with det cord that is set off with a blasting cap whose detonation rate is in the miles per second as was correctly noted. But my point is that it doesn't explode or detonate the way an explosive does. Don't confuse black powder which does explode with smokeless powder. I think that's where the confusion is.

[W.R.Buchanan]

Det cord runs around 30,000 fps. C4 is around 32,000 fps. The rule of thumb I was told was that you pick an explosive that is at least 5,000 fps faster than the Resonance Frequency of the thing you are trying to blow up. I have seen a video of a guy using Det Cord to cut a piece of I beam and it looked exactly like it was cut with a torch.

I know that smokeless powder is affected by the pressure generated within its containment area, however the major explosive component in smokeless powder is Nitro Glycerin which is an Explosive. A quick search said Nitro when in an absorbent (dynamite) runs between 10,000 and 20,000 Fps.

My point here is there must be some "Empirical" way to measure it.

When I was younger and lived alone I had this little glass ash tray. everytime I got a new can of powder I would put a small pile of it in the ash tray and set it on the fence in my Foyer outside my front door. I'd light a match and toss it in and watch the powder fizz and burn. NO pressure to support and accelerate combustion.

I did this for years until I tried it with a small pile of Black Powder,, which instantly blew up in my face, and I literally looked like Black Sambo !

Never did that again !!!

Randy

[longbow]

The deflagration of smokeless powder is a lot slower than a detonation. In the definition of deflagration of powder it says subsonic flame propagation but that doesn't quite make sense... I don't think. The gas has to be expanding at the bullet velocity and the whole works from primer strike to bullet leaving the bore happens in milliseconds. However, you certainly do not want your smokeless powder detonating. That would be bad!

Regardless of what the test method is to develop burn rate charts they are relative. That doesn't mean that three consecutive powders are separated by the same gap in burning rate though. The three powders may have almost identical burn rates, the middle powder may have the same burn rate as either other powder and the gap between it an the other may be large. For instance H4227 and IMR4227 are listed sequentially in powder burn rate charts I have yet they have the same burn rate (within lot to lot variation anyway). I am sure there are lot of other examples too.

But yes, regardless of whether comparative rate is inches/second, grams/second, cc's/second or something else would be interesting to find out.

Hah! Not quite the same but similar. When I was young and foolish I decided that watching a SMALL amount of smokeless powder burning in a vessel might be interesting. The only handy vessel was a beer bottle so... I put a SMALL amount of IMR4198 (IIRC) inside (I'll say maybe 10 to 15 grs. thinking back) and ran a home made fuse to it. The powder lit and flared up a bit but no obvious pressure in the open top bottle not a lot different than burning in open air. So, (yes, I did it!) I added a BIT more powder since the first time was pretty uneventful. This time it was pretty obvious that the flame/flash over was quite a bit more dramatic and the bottle broke... not from pressure but heat. However, the difference in the burn was startling. That extra bit of powder was enough to fill the interior with fire and have it coming out the mouth of the bottle, though not rocket motor like, this was a quick WHOOSH! I am guessing that probably flashover and disturbance of the powder resulted in more surface area burning faster. This was certainly not a closed high pressure chamber but still quite a difference in combustion between the two very unscientific tests.

As the saying goes... Good judgement comes from experience and a lot of that comes from bad judgement! Sometimes I am surprised I still have most of my original body parts but I tend to also learn fairly quickly not to repeat some experiences! I do normally take reasonable precautions but I have to think that some luck has been involved!

Longbow

[W.R.Buchanan]

"Regardless of what the test method is to develop burn rate charts they are relative. That doesn't mean that three consecutive powders are separated by the same gap in burning rate though. The three powders may have almost identical burn rates, the middle powder may have the same burn rate as either other powder and the gap between it an the other may be large. For instance H4227 and IMR4227 are listed sequentially in powder burn rate charts I have yet they have the same burn rate (within lot to lot variation anyway). I am sure there are lot of other examples too."

This is exactly why I want to know what the gaps are. I am pretty sure the gaps are not consistent.

Randy

[fcvan]

Det cord runs around 30,000 fps. C4 is around 32,000 fps. The rule of thumb I was told was that you pick an explosive that is at least 5,000 fps faster than the Resonance Frequency of the thing you are trying to blow up. I have seen a video of a guy using Det Cord to cut a piece of I beam and it looked exactly like it was cut with a torch.

I know that smokeless powder is affected by the pressure generated within its containment area, however the major explosive component in smokeless powder is Nitro Glycerin which is an Explosive. A quick search said Nitro when in an absorbent (dynamite) runs between 10,000 and 20,000 Fps.

My point here is there must be some "Empirical" way to measure it.

When I was younger and lived alone I had this little glass ash tray. everytime I got a new can of powder I would put a small pile of it in the ash tray and set it on the fence in my Foyer outside my front door. I'd light a match and toss it in and watch the powder fizz and burn. NO pressure to support and accelerate combustion.

I did this for years until I tried it with a small pile of Black Powder,, which instantly blew up in my face, and I literally looked like Black Sambo !

Never did that again !!!

Randy

What Randy said. I worked with a guy who was at the time and electrician, but in a previous life an EOD Instructor. Umpteen years ago, he would provide an overview class on explosives and such, and improvised devices.

I was the training manager at a Maximum Security facility where we housed the SLA LAX Bomber, doing life for that early 1970s event. That guy was caught on many occasions with pre-cursor bits and parts for IEDs. The training was designed to open the eyes of officers when conducting cell searches.

He also did a review of normal cleaning agents and things, and then recommended suitable replacements. Still, as booliteers, we know you need an oxidizer, a carbon source, and an ignition source. We don't need to look hard to find directions. Neither do inmates, it was like pulling teeth to get the encyclopedias redacted regarding the making of Black Powder, and that effort failed. There was the argument raised that we locked up bubbas as well as bombers, the knowledge was already out there. Most of those things needed are harmlessly sold at the commissary every month.

Oh, and the correct term is 'blast wave velocity' which is different than PSI. The propellant creates extreme pressure if contained, cartridges are designed to contain the components, and release the pressure when ignited, in a controlled fashion. What we do is in a small way, 'fluid dynamics' and I supposed so is bomb making. Energy flow is energy flow, what we do is use the right tool for the job, that tool is assembly of components to complete a rather complex result. That is why we use 'recipes' that have been lab tested by professionals to ensure we don't detonate, but ignite and control.

[BrutalAB]

I wouldnt be terribly surprised if we could find two powders where under open burn, powder a was faster, but under confined burn, powder b was faster.

It is neat to compare open burn speeds of 700x to superformance. Its quite a difference.