Is excess powder really blown out?

[Artificer]

I think the MYTH that black powder doesn’t burn up entirely in the barrel (actually very near the original position at the breech) came/comes from two things:

1. Tests of firing black powder guns over cloth or snow and not realizing the “Grains” of the Ejecta were either already burnt up or would not burn up. Some grains that might burn later were coated or partially coated with the residue from other burnt powder and that kept them from burning inside the barrel as well.

2. Longer barrels provided higher velocity in the same caliber and when using same powder charge. Many people back then and unfortunately some people today erroneously think this is because the powder continues to burn throughout the length of the barrel. That is not true.

The following is a layman’s explanation of what goes on inside the barrel.

The burning powder causes propellant gas and like any gas, it expands to the size of its container. (Boyle’s and others Gas Laws.) As the propellant gas expands, it provides physical force against the patched ball or other projectile.

When the patched ball is at rest, it takes the greatest amount of force to begin moving it, BUT it takes less force to increase its speed once it gets moving. Most people have pushed a vehicle, so I will use that as an example. It takes more force to push it to get it to begin moving than it does to keep it moving or even increase the speed of moving on a flat road.

The propellant gas continues to apply force to the projectile, as long as the projectile it is confined in the barrel. This even though the force of the gas decreases as the projectile goes down the barrel, due to the larger size of the “container” the gas expands into, there is also less force needed to keep increasing the velocity in the barrel as it goes down the barrel. Thus the projectile is still increasing in velocity until it exists the muzzle and the gas disperses into the atmosphere.

Now, if the barrel was long enough, the friction of the projectile acting against the bore would eventually slow it down even with the propellant gas still acting on it inside the barrel, but the barrel length would have to be much, MUCH longer than any gun barrel that can be carried by a single man.


Gus

 

[Britsmoothy]

I think the MYTH that black powder doesn’t burn up entirely in the barrel (actually very near the original position at the breech) came/comes from two things:

1. Tests of firing black powder guns over cloth or snow and not realizing the “Grains” of the Ejecta were either already burnt up or would not burn up. Some grains that might burn later were coated or partially coated with the residue from other burnt powder and that kept them from burning inside the barrel as well.

2. Longer barrels provided higher velocity in the same caliber and when using same powder charge. Many people back then and unfortunately some people today erroneously think this is because the powder continues to burn throughout the length of the barrel. That is not true.

The following is a layman’s explanation of what goes on inside the barrel.

The burning powder causes propellant gas and like any gas, it expands to the size of its container. (Boyle’s and others Gas Laws.) As the propellant gas expands, it provides physical force against the patched ball or other projectile.

When the patched ball is at rest, it takes the greatest amount of force to begin moving it, BUT it takes less force to increase its speed once it gets moving. Most people have pushed a vehicle, so I will use that as an example. It takes more force to push it to get it to begin moving than it does to keep it moving or even increase the speed of moving on a flat road.

The propellant gas continues to apply force to the projectile, as long as the projectile it is confined in the barrel. This even though the force of the gas decreases as the projectile goes down the barrel, due to the larger size of the “container” the gas expands into, there is also less force needed to keep increasing the velocity in the barrel as it goes down the barrel. Thus the projectile is still increasing in velocity until it exists the muzzle and the gas disperses into the atmosphere.

Now, if the barrel was long enough, the friction of the projectile acting against the bore would eventually slow it down even with the propellant gas still acting on it inside the barrel, but the barrel length would have to be much, MUCH longer than any gun barrel that can be carried by a single man.


Gus

Perfect.
Some 22 ammo will shoot faster in a short barrel than it will in a longer barrel.
Not by much, but it can be demonstrated.

 

[Artificer]

I've read that about 14 inches of barrel for a .22 gives the maximum velocity, but of course that is with a different propellant powder in modern times. I don't know about ML .22 caliber rifles, like an extremely unusual original Hawken rifle I saw many years ago on display in Denver. Tiny little round balls.

Gus

 

[Danny Ross]

There is residue left after anything that is a solid material that burns. Look at a wood fire you either have white ash from completely burned wood or small pieces of charcol. Charcol is just an incomplete burn of the material. I would assume it would be the same with black powder burning. The part closest to the oringinal ingition point would have the longest burn time to burn more completely and be the black powder "white ash". The powder futher away from the ingition point would have the shortest burn time and still have some subtance left to it, black powder "charcol". It is burnt, just an incomplete burn (which would be seen in the snow or on a white sheet. If burning was not still occuring we would not have any flame coming out the end of the barrel when the shot occurs because all material and gases would have been comsumed completely by the heat. We also would have no real residue left in the barrel that would increase the amount of pressure needed to load the projectile at anytime. DANNY

 

[zimmerstutzen]

If all the powder is consumed/burned in those first few inches, then there would be no reason for the diminished velocity increases, except the decreased length of the bore traveled by the ball. However, when the amount of powder goes up beyond the point where velocity gains are reduced, the fouling in the barrel is increased. Normally that occurs when the powder is not burning under pressure. That would seem to indicate that powder is still burning after the ball exits the muzzle. I remember reading something about getting increased pressure from black powder depending on where in the length of the powder column the ignition was started. In most guns the ignition is very close to the rear. of the lets say 1.5 inches of powder in the bore. But when the ignition was introduced at the middle of that charge column, pressures increased.A member on this forum did some tests about the speed of ignition based on where the prime was located in the pan. As I recall, the time was something approx, 3 hundredths of a second. Nearly instantaneous to most humans. But still taking a period of time for the prime to lite the charge and the charge to burn forward through the length of powder in the bore. If the ignition is introduced at the half way point, does the powder, burning both forward and rearward burn faster. If it increases pressure over charges ignited just from the rear, it would seem to be as a result of the powder burning both forward and rearward from the middle. A conclusion would be that powder burns, very quickly, but still takes a period of time to burn from the rear of the charge to the front. Does it burn faster than the time it takes to push the ball down the bore to the muzzle? Does the increase in powder past the point of diminishing returns mean it takes longer for the ignition to burn it's way through the powder column in the bore.

 

[Artificer]

If all the powder is consumed/burned in those first few inches, then there would be no reason for the diminished velocity increases, except the decreased length of the bore traveled by the ball. However, when the amount of powder goes up beyond the point where velocity gains are reduced, the fouling in the barrel is increased. Normally that occurs when the powder is not burning under pressure. That would seem to indicate that powder is still burning after the ball exits the muzzle. .

I am not entirely sure I'm following what you mean?

Velocity increase is not a straight upward line on a chart as the powder charge is increased, With each increase of powder, the velocity still goes up, though granted not as much of a change at the very highest charges as at the lower charge range. At the higher powder charge levels, there is a point where the barrel length is not long enough to get as significant increases in velocity as you got at the lower charge increases.

I can see how powder ignited in the center of a powder column gives higher pressure than a column ignited at the rear end. The powder with more central ignition is burning both backwards and forwards in the powder column at the same time. This means the powder will burn faster and thus give higher pressure.

Gus

 

[SDSmlf]

Ok, I am ready to get kicked around so here is my opinion. Do I really care whether or not all the powder is burned in the barrel? No. Big ‘N’, little ‘o’. All I care about is accuracy and maximum velocity. How much powder of a specific grade under a projectile in a certain length barrel gives me the best accuracy? Who cares about amount of unburned powder if you have a hard hitting accurate load? Missed what I was shooting at, but burned all my powder.……

For what it is worth, have learned to love Swiss. Use mostly fff for everything. Just one opinion.

 

[zimmerstutzen]

"All I care about is accuracy and maximum velocity" two rather opposing concepts. Hunters don't give a manure about accuracy as long as it is minute of deer. Velocity of a round ball is also partially counter productive once sonic speeds are passed. Deceleration due to air resistance increases substantially with muzzle velocity. Sure that extra 30 grains gives you a somewhat flatter trajectory at 100 yds, but by 120 it is still a rainbow.

 

[zimmerstutzen]

I am not entirely sure I'm following what you mean?

Velocity increase is not a straight upward line on a chart as the powder charge is increased, With each increase of powder, the velocity still goes up, though granted not as much of a change at the very highest charges as at the lower charge range. At the higher powder charge levels, there is a point where the barrel length is not long enough to get as significant increases in velocity as you got at the lower charge increases.

I can see how powder ignited in the center of a powder column gives higher pressure than a column ignited at the rear end. The powder with more central ignition is burning both backwards and forwards in the powder column at the same time. This means the powder will burn faster and thus give higher pressure.

Gus

When black powder is burned uncontained, it leaves more fouling residue. When a person shoots a patch ball combination that is too loose, powder fouling goes up to nearly the same as if the charge was shot with no patch or ball. When a charge burns nearly completely before a tight patch ball combination exits the muzzle, there is far less fouling in the bore. When a person exceed 100 grains in a 28 inch barrel the fouling also goes way up. To me, that demonstrates that a goodly portion of the powder is burning without the containing pressure of the ball ahead of it. IE, after the ball has left the muzzle. You certainly are not maintaining that the muzzle flash does not increase with charges beyond that point of diminished returns, or are you? More flame and debris at the muzzle means less complete combustion to me.

 

[zimmerstutzen]

Lyman 1st Ed page 96. 45 cal barrel, 28 inches long. C&H powder
80 grs MV 1921 ME 1088 100 yard energy 314
90 grs 1979 1154 328
100 grs 2037 1223 344
110 grs 2042 1229 345
120 grs 2048 1234 346
130 grs 2052 1241 348

Take notice how the last 40 grains resulted in negligible difference in velocity and 100 yd energy. ie it is rather irrational to keep packing in higher loads.

 

[George]

Ok, I am ready to get kicked around so here is my opinion. Do I really care whether or not all the powder is burned in the barrel? No. Big ‘N’, little ‘o’.

I'm curious. If you don't care, why are you in this thread? It's clearly labeled, "Is excess powder really blown out?". I would think only people interested in the answer to the question would join in the discussion, yet you seem to have chimed in just to tell us you don't care.

Spence

 

[George]

Take notice how the last 40 grains resulted in negligible difference in velocity and 100 yd energy. ie it is rather irrational to keep packing in higher loads.

Think about this...it may be partly due to the fact that the percentages change if you continue to add a fixed amount of powder. As an example, if you start with 40 grains and add 10 grains, you have added an amount equal to 25% of the starting load. Continue doing that 10 grains at a time, and when you get to 100 grains, the next addition will be only 10% of the previous load. It's not logical to assume the velocity increases will continue the same throughout the exercise. Of course the increases will become smaller as you go along. I've never seen anyone try adding a fixed percentage instead of a fixed weight. What would the velocity do if you added 25% to that 100 grain charge, shot 125 grains instead of 110?

Spence

 

[M. De Land]

Lyman 1st Ed page 96. 45 cal barrel, 28 inches long. C&H powder
80 grs MV 1921 ME 1088 100 yard energy 314
90 grs 1979 1154 328
100 grs 2037 1223 344
110 grs 2042 1229 345
120 grs 2048 1234 346
130 grs 2052 1241 348

Take notice how the last 40 grains resulted in negligible difference in velocity and 100 yd energy. ie it is rather irrational to keep packing in higher loads.

My best patched ball load in my .45 caliber target gun seems to be right at 65 grains of 3F Goex. Looks like from the Lyman loading manual that about 100 grains reaches the diminishing returns plateau.

 

[Carbon 6]

Assume for a minute that powder burns at a specific velocity.

The velocity of the ball is determined by the amount of pressure created.

As the ball travels down the barrel the volume of space increases lowering the pressure.
if you add more powder to create more pressure to create a faster velocity, the volume related pressure drop will eventually out pace the velocity.

Why?

Because the velocity of deflagration (burning) is limited. (this is the fundamental difference between black powder and smokeless. Smokeless doesn't burn or deflagrate, it detonates.)


Powder only burns so fast, at some point adding more won't result in any projectile velocity gains.( Unless other things are changed.)

 

[SDSmlf]

"All I care about is accuracy and maximum velocity" two rather opposing concepts. Hunters don't give a manure about accuracy as long as it is minute of deer. Velocity of a round ball is also partially counter productive once sonic speeds are passed. Deceleration due to air resistance increases substantially with muzzle velocity. Sure that extra 30 grains gives you a somewhat flatter trajectory at 100 yds, but by 120 it is still a rainbow.

Agree accuracy and maximum velocity are opposing concepts. Nature of the game. We need them both.

Ok, I have a 30 grain load under a 58 caliber round ball that will give a squirrel a headache at 25 yards every time. Well within minute of deer at 25 yards. And likely subsonic (no, I have not checked with a chronograph). Am I there?

Or do I increase the powder charge until groups start to open up (or shoulder pain says to stop) at lets say 75 or 100 yards, then back off a bit for a hunting load after checking accuracy/trajectory at midrange (something less than 3” high)? I would call this my deer hunting or accuracy load at max velocity. My load for my gun with my components giving the performance I need. Don’t care about super or sub sonic. Not worried about burnt or unburnt powder in front of barrel. Not worried about the 120 yard shot. 100 yards under perfect conditions is it for me with a round ball.

 

[SDSmlf]

I'm curious. If you don't care, why are you in this thread? It's clearly labeled, "Is excess powder really blown out?". I would think only people interested in the answer to the question would join in the discussion, yet you seem to have chimed in just to tell us you don't care.

Spence

Interesting discussion. I just don’t believe whatever (burnt or unburnt) is blown out of the barrel is necessarily an indicator of accuracy performance. Shooting over snow I have seen some loads (specifically Pyrodox if memory is correct) spraying powder residue in front of the barrel of one of the most accurate ML shooters I have known. It was always more of a ‘hey, look at this’ topic when it came up. A byproduct of the powder being used. Used to shoot over fresh lake effect snow a lot when I lived in Upstate NY.

 

[Artificer]

Think about this...it may be partly due to the fact that the percentages change if you continue to add a fixed amount of powder. As an example, if you start with 40 grains and add 10 grains, you have added an amount equal to 25% of the starting load. Continue doing that 10 grains at a time, and when you get to 100 grains, the next addition will be only 10% of the previous load. It's not logical to assume the velocity increases will continue the same throughout the exercise. Of course the increases will become smaller as you go along. I've never seen anyone try adding a fixed percentage instead of a fixed weight. What would the velocity do if you added 25% to that 100 grain charge, shot 125 grains instead of 110?

Spence

Spence,

That is an excellent point !! As the charges go up into the higher end, small increases in powder are also a smaller percentage of the entire power charge. So the increase in velocity will not go up as sharply as it did near the lowest amounts of powder used.

Gus

 

[Artificer]

When black powder is burned uncontained, it leaves more fouling residue. When a person shoots a patch ball combination that is too loose, powder fouling goes up to nearly the same as if the charge was shot with no patch or ball. When a charge burns nearly completely before a tight patch ball combination exits the muzzle, there is far less fouling in the bore. When a person exceed 100 grains in a 28 inch barrel the fouling also goes way up. To me, that demonstrates that a goodly portion of the powder is burning without the containing pressure of the ball ahead of it. IE, after the ball has left the muzzle. You certainly are not maintaining that the muzzle flash does not increase with charges beyond that point of diminished returns, or are you? More flame and debris at the muzzle means less complete combustion to me.

First, thank you for the additional explanation.

Muzzle Flash will always increase as the powder charge goes up, because muzzle flash is the propellant gas hitting the oxygen rich atmosphere. More powder means more propellant gas in the bore, thus a greater muzzle flash as long as the ball and patch remain consistent.

You wrote: “When a person exceed 100 grains in a 28 inch barrel the fouling also goes way up.”

Please understand I’m not trying to be nitpicky, but how do you quantify how much the fouling goes up and is that comparing shots from a clean bore each time the rifle is fired with an increased powder charge? What types and grain size of powder is being used? How are environmental conditions controlled to come up that theory?


Gus

 

[Artificer]

I would like to apologize to the forum for something I have written that may be confusing to other members on this topic.

I have written that all the powder in the bore burns up in the first few inches. That is correct, but perhaps I should have written “all the powder in the bore, that is going to burn up in the bore, will burn up in the first few inches.”

There will be grains of Ejecta from even the lightest powder charges. If one doesn’t believe that, then shoot a light charge over snow or a light colored ground cloth.

Now, if people believe the powder burns all the way down the barrel, then there should be virtually no grains of Ejecta with light powder charges. True, there is not as much Ejecta as in heavier powder charges, but that is due to what the Ejecta Grains are; I.E. burnt pieces of fouling, grains that did not have enough saltpeter in or near them to ignite or grains that got coated with residue and thus would not burn up in the bore, no matter how long the barrel the barrel length. So heavier charges of powder will give a larger amount of Ejecta.

I think everyone can agree the highest temperature of the powder burning and the highest pressure of the propellant gas is near the breach of the barrel. Thus any powder that actually will burn in the bore, does so close to the breech.

Gus

 

[George]

This from the same caliber of scientists who bled deathly ill people to make them better and believed tomatoes were deathly poisonous.

I noticed that the probe New Horizons is headed for a new amazing event. That probe was launched in 2006, swept by Jupiter in 2007 close enough to get a velocity boost from Jupiter's gravity, arrived at the most distant planet, Pluto in 2015, and now, 3 years after that, is headed for an object in the Kuiper belt only 19 miles in diameter but 4.1 billion miles away. This is possible in large part because Isaac Newton published his Principia in 1687 laying out the basic theories and math upon which it is built.

The basics of the ballistics we are all so much interested in were worked out by a lot of smart men, especially Benjamin Robins. He laid down the foundation for modern ballistics early on in the 18th century.

It's possible that we should not paint early scientific accomplishments with quite so wide a brush.

Spence