Unburnt powder

[Baxter]

I'm reading about powder charges in .54 cal barrels. I got my .54 cal ML start with a CVA percussion 'Mountain Rifle' and used a 100gr loading of Pyrodex in 100gr equivalent to black powder. Recoil was a solid 'thump' but nothing worse. I never used real black powder nor did I try putting a white sheet out beyond the muzzle to catch/see the unburnt propellant. I've been advised to try 50gr of 'real blackpowder' as a starting load in my soon to me new .54 with a prb. Does anyone check 'unburnt powder' as a measure of efficiency now?

 

[biliff]

Not going to get into the legitimacy of the "unburnt powder on a sheet test".

Efficiency is nice but accuracy and energy are your primary goals.

And no, I don't do the test and probably never will.

 

[buford87]

Personally I think the unburnt powder test is a myth. If powder is blown out of the muzzle whilst unburned it will be burned before it hits the ground. Look for a load that is accurate and gives you enough energy for the job you ask of it. An old rule of thumb for a starting load is from one-third to one-half of the weight of the ball in powder. This is for round balls since conicals would give a much higher weight of powder which could very well be an overload................watch yer top knot...............

 

[bob308]

yes i have done it over snow. with some of the loads i see people saying they are using. there is alot of unbruned powder.

another way is to use a chronogragh. go up i 5gr. steps when you stop getting large increases in volices. you have reached the best load.

 

[Claude Mathis]

Efficiency is nice but accuracy and energy are your primary goals.

I agree. Once I achieve my most accurate load, I don't care what percentage of the powder is burning, what the velocity is, or what the muzzle energy is. I know for sure my target wont care. :wink:

If your most accurate load means there's some unburned powder, then perhaps that's what is required?

 

[Stumpkiller]

You should get most or all of a 85 gr load of FFg burnt in a .54 barrel of 30" or better. Likely more.

 

[Oldnamvet]

I wonder if anyone has collected this supposedly unburnt powder and touched a match to it? I am betting it is mainly fouling that is getting blown out of the barrel and will not ignite.

 

[mooman76]

I'm thinkin that rather than unburned powder what you would find is poorly burned powder. I'm not going to argue the point though because to me it would be a worthless argument and like other have said the point is for the most accurate load so if there is a little poorly or unburned powder, then it is what it is.

 

[Greenjoytj]

Considering how volatile/easy to ignite BP is, I doubt very much that the granules of black manure that maybe seen when a muzzle loader is fired over snow is unburned BP. I say its just ash or fouling.

Try firing a night and have some one watch or video the the rocket exhaust exiting the muzzle. Sure there will be particles of powder still burning on muzzle exit, but they were also burning inside the barrel to which means they were doing their job and making gas pressure, and making pressure is what burning powder is all about, I want the pressure to be building higher and higher all the way to the muzzle. If that means some of the fuel is still being burnt outside the barrel so be it. That's my indication that the pressure inside the barrel was still building.

 

[54ball]

I see this as one of those theories that has some basis in truth. It's one of those things that may can be figured out on paper but in the real world, its not really true.
Two examples....
Friction loss
In the fire service a pump opperator has to adjust his pump and pressure for friction loss. The longer and smaller the hose the more pressure is needed to over come the friction. Theoreticaly the friction will over come the pressure if the hose is long enough. In thoery at this point you can unscrew the hose and see the water, stagnant. This is simply not true, you may not have enough pressure and flow to fight a fire but the water will not be stagnant.
Cars
Using a big 4bbl carb on a stock 2bbl car.... Theory the stock 2bbl car can only use a so much gas as the design will allow. Any more, is simply blown out the tailpipe.
The car may have no drivabilty and will foul plugs but if you can get it to a cruising RPM It will out perfom the smaller carbs. Most the gas may be blown out the tail pipe but more importantly more is used.
Same with a rifle. More powder may be blown out the bbl but at the same time a higher volume is burned with the higher charge.

The reason this turns to theory is these massive charges may indeed have velocity, but shootabilty, safety and accuracy go bye bye at these heavy charges.
Why shoot 175grns with rocket velocity and washing machine size groups at 50 yards when you can use 80 grns and put em all in a coffee cup at 100yrds.

 

[George]

I wonder if anyone has collected this supposedly unburnt powder and touched a match to it? I am betting it is mainly fouling that is getting blown out of the barrel and will not ignite.

Something very like that has been done, and a long time ago. In 1743, to be exact, and by no less a spiffy group than the Royal Society of London, of which Sir Isaac Newton had been president only a few years before.

From "An Essay on Shooting", Wm. Cleator, 1789, in a discussion of the mistaken reasons for long barrels:

From the theory we have just given a detail of, it appears that the superior range of long barrels was founded intirely upon the opinion, that the powder fires gradually all the time it is passing through the barrel. The conclusion necessarily drawn from this, was, that the larger the charge, the longer time it was in kindling; and hence, that for any assigned charge, the barrel must be of a proportional length, so that the powder may be completely inflamed just as the ball or shot are about to quit the muzzle: The converse of this proposition was, that in every piece there is a certain charge which will be all fired just at the parting of the ball or shot from the mouth of the piece, and that any addition of powder will not take fire, but will only serve, by its weight, to diminish the action of the rest, and consequently, to retard the velocity of the shot or ball,
If this matter be considered with mathematical rigour, it must certainly be allowed, that, as the fire is not at once applied to every particle of the powder, the whole of the charge cannot be inflamed at the same instant; but it is equally certain, that the progress of the inflammation is so rapid, that the powder is completely kindled before the ball or shot arrives at the mouth of the shortest barrel ever made use of.
To determine this, a number of experiments were made by a committee of the Royal Society, so long ago as the year 1743 and by these it was shewn, that when a barrel was shortened so much that the ball placed before the powder was upon a level with the muzzle, the unfired powder, collected from the discharge, by means of a cloth spread before the piece, weighed but one twelfth of the charge. This was analysed, and found to contain less saltpetre than an equal portion of the same powder did. Hence, and from the extreme minuteness of the particles collected, there was reason to believe, that the grains to which they belonged were less susceptible of inflammation than the rest, owing, perhaps, to some inequality in their mixture: what served in a great measure to prove this, was, that when the charge, and consequently the heat generated during the explosion, was increased, the quantity of unfired powder collected was proportionally smaller. And we may therefore safely conclude, that the powder is completely inflamed before the ball or shot arrives at the mouth of the shortest barrel ever employed.

Spence

 

[Musketeer]

I recall reading (Fadala's BP Handbook) that only about 50% of BP is actually converted to gas upon ignition, while the other half burns but is not completely consumed. It still does its share in the propulsion process, however. As others said above, I believe what people are seeing on the sheet are these burnt but not totally consumed grains of powder, NOT "excess" unburned granules. :hmm:

 

[russecv58]

my 2cents on the subject is this: i've stood by and watched my son shooting my 54 cal GPR with only a 30 grain charge of 2f Goex bp/.535rb/.020 patch, and to my supprise i watched as bright glowing particles of powder dropped within a couple feet of the muzzle into some nice dry grass. :shocked2: luckily it didnt start any fire. so my guess would be that these were the small ammount of granuals of powder that came into contact with the lubed patch, thus causing them to burn slower due to, dare i say lube contamination, however minute it may have been. i think this is what alot of people are refering to as "unburnt" or "wasted" powder. now i could see if it were an excessive ammout, but under normal loading conditions, i think the "efficiency" talk is alot of BS. thats my theory anyway :v

 

[Joel/Calgary]

I recall reading (Fadala's BP Handbook) that only about 50% of BP is actually converted to gas upon ignition, while the other half burns but is not completely consumed. It still does its share in the propulsion process, however. As others said above, I believe what people are seeing on the sheet are these burnt but not totally consumed grains of powder, NOT "excess" unburned granules. :hmm:

You'll get more detail from reading the "Mad Monk", but what they're talking about is the amount that forms potassium carbonate, potassium sulphate, and the other solids that form the fouling & smoke, rather than the gasses that actually propel the projectile. That said, I have read postings on various forums by shooters who seemed to be reliable witnesses and who claimed to have performed the shoot-over-a-sheet experiment, and they reported having recovered small amounts of unburnt powder, the test being that it flashed when ignited. To complicate things, the Mad Monk found that at least some of the sparks seen at night or in high-speed photos are not burning powder grains per se, but rather glowing larger-size chunks of inadequately-milled charcoal.

Regards,
Joel

 

[Larry Pletcher]

. . . cut quote . . .To complicate things, the Mad Monk found that at least some of the sparks seen at night or in high-speed photos are not burning powder grains per se, but rather glowing larger-size chunks of inadequately-milled charcoal.

Regards,
Joel

I experienced this in a photography session when trying to photograph a patch separating from a ball. Using Goex ffg, the amount of sparks made it impossible to see the ball. I was ready to give up, but instead I spoke to Mr. Knight about this. His reply was to switch powders and use Swiss.

His explanation was that I was seeing charcoal particles burning in front of the muzzle. Swiss charcoal is ground much finer than Goex, and that a switch to Swiss would greatly reduce the sparks. Bill suggested an experiment that would demonstrate this:

Disolve a quanity of Goex powder in water in a container. Stir until everything that that will, is disolved. Rub a spoon over the bottom of the container and you can feel the undisolved carbon. Repeat this with Swiss and you can't feel anything on the bottom.

I switched to Swiss and the spark level was dramatically reduced. We eventually got the photo I wanted using Swiss.

I agree with Joel then, that sparks seen are burning charcoal. Below is a link to the process I went through to finally get the patch separation shot. (You will see a lot of failed shots before we switched to Swiss.)

Patch Separation Shot

Regards,
Pletch

 

[MSW]

Pletch, thanks for the post. Your photos are WAY COOL!

:thumbsup: :hatsoff: :grin:

 

[Billnpatti]

That was a fantastic article, Larry. Amazing photos ! You never cease to amaze me with your experiments. Keep up the wonderful work and keep publishing your results. :thumbsup:

 

[Dean2]

Burned or not, the suggestion to shoot loads increasing by 5 grains per till the speed increase drops below 30 fps per 5 grain increase, is the best suggestion yet. (Try it with both FFFG, and FFG depending on claiber. You may also want to try the same experiment with Swiss and Goex. Do not exceed the manufacturers suggested max load for the gun) At this point you have found the maximum useful charge. Work back from there to find an accurate hunting load, and back further to find an accurate and milder target load.

 

[ebiggs1]

What these guys said............

Personally I think the unburnt powder test is a myth. If powder is blown out of the muzzle whilst unburned it will be burned before it hits the ground

.

Considering how volatile/easy to ignite BP is, I doubt very much that the granules of black manure that maybe seen when a muzzle loader is fired over snow is unburned BP. I say its just ash or fouling.

I agree that the gun does what you want it to and whatever powder or efficiency is secondary. Actually, over loaded muzzle loaders become flame throwers!

 

[Dphar]

Efficiency is nice but accuracy and energy are your primary goals.

I agree. Once I achieve my most accurate load, I don't care what percentage of the powder is burning, what the velocity is, or what the muzzle energy is. I know for sure my target wont care. :wink:

If your most accurate load means there's some unburned powder, then perhaps that's what is required?

Exactly.

Dan