How much energy is lost from unburnt powder

[psijac]

I'm just curious. Does anyone know?

[jimlongley]

I don't know how it works with smokeless powder, but with black powder there comes a point, as you dump more powder down the bore, where you have passed beyond diminishing returns and are actually using powder to shoot powder. As an example: Back before low priced chronographs became almost universally available, I would work up a load by laying a sheet on the ground in front of my muzzle, and shooting over it. I would start with a nice conservative "recommended" load and then start adding 5 grains or so, by measure, each time, until I began to see unburned powder on the sheet. Unburned powder means that you are using some on the energy from the burned powder to push extra powder down the bore and you might as well stop adding more. The cost in terms of energy is probably minimal, that little extra powder does not weight much, but why throw it away?

Having achieved the maximum load I would then start backing down, firing several shots at each level, until I found the one that was most accurate for my purposes.

BTW, lately I have tried a BP "substitute" only to discover that it REALLY is a poor substitute if you are using a flintlock.

[OldCannon]

BTW, lately I have tried a BP "substitute" only to discover that it REALLY is a poor substitute if you are using a flintlock.

Friends don't let friends use "fake" black powder in their smokepoles

That reminds me, I'm WAY overdue to take my black powder toys out and have some fun. I need to cast some more minies and go have a blast

[jimlongley]

BTW, lately I have tried a BP "substitute" only to discover that it REALLY is a poor substitute if you are using a flintlock.

Friends don't let friends use "fake" black powder in their smokepoles

That reminds me, I'm WAY overdue to take my black powder toys out and have some fun. I need to cast some more minies and go have a blast

Yeah, unfortunately my last can of FFFg was running low and I was on my way to a Civil War Encampment, so I stopped by Cabella's. Turns out that: 1) Most of their employees don't even know what real BP is; 2) Most of their employees don't know what they are talking about when it comes to BP; and 3) They don't carry real BP anyway. So I took a pound of this other crap and tried to return it, but they wouldn't take it back opened.

[TheCytochromeC]

I assume you're talking about the Muzzle Energy, the kinetic energy of a bullet them moment it leaves the barrel. You'd think it'd be directly proportional to the amount of unburned powder. As in, 10% un burned powder results in 10% drop in ME. I don't think this is the case. If I'm not mistaken, it would be a logarithmic curve. As in, as in the energy sharply increases upon the addition of powder to the case, but reaches the max velocity and ME and plateaus off. So, in my crazy head, I'd say an amount you'd have a difficult time observing or measuring ;)

I should also add, if you're referring to that occasional black sooty speck that you can tap out of some cases once they're fired, I'd also say that's negligible. Most of the energy was sucked out of that guy, which is why he's sooty. In just about evey case, the powder is completely burned. You don't really see the pellets or flakes that you started with. What does vary quite a bit is the consistency with which the powder burns. This can have a greater impact on accuracy and ME greater than un-burned powder

[mrvmax]

I have never paid too much attention to it but the Quickload program will predict how much powder is not consumed according to the data you enter. It is really a good program to have if you reload since you can play with different parameters to see the effect of changes.

[WildBill]

I'm just curious. Does anyone know?

What you would have to do it to collect all of the unburned powder and weigh it. Then you could calculate the energy loss.
Collecting the unburned powder - and measuring it - that's the hard part!
As jimlongley describes in his post above, it could be done by collecting it on a white sheet.

[suthdj]

Theory- If we know how fast the powder burns, how fast it travels up the barrel. how long the barrel is, you should be able to calculate the point at which the burning powder is doing nothing(bullet left the barrel)

Mind you I know nothing. It is just an idea.

[OldCannon]

Theory- If we know how fast the powder burns, how fast it travels up the barrel. how long the barrel is, you should be able to calculate the point at which the burning powder is doing nothing(bullet left the barrel)

Mind you I know nothing. It is just an idea.

Doesn't quite work that way. "Internal Ballistics" involve some VERY weird math. Generally speaking, your best resource is the powder manufacturer, who can give you an idea of powder burn rates and what you would approximately get depending on cartridge and length of barrel. Me, I would be FAR less worried about unburnt powder than I would be with overpressure situations, with modern propellants.

[Stratman]

Sorry I cant help. Thinking about how much powder is not burned is just one of those subjects that never enters into my thinking. But hey, maybe its just me.

[mrvmax]

If I can remember I will pull some data from Quickloads and post it.