Malachi Leviticus Blue
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Black Powder makes a great filler, yep just fill 'er er up
Disproving the myth of "Air Gap is dangerous" for Black Powder Cartridges
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hawg
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All the more reason to fill it up with bp.
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Good thread. I think air gap is more relevant when you have an obstructed bore and a fresh newly fired oncoming object. The compression is between the obstruction and the fresh oncoming object. But I'm no scientist and certainly not a physicist.
The air gap between the power and the bullet is of less consequence. The idea behind a filler in more modern reloads is to get more consistent ignition. The gallery loads discussed is almost like a squib load. Is there sufficent power to genetrate the gases that will dislodge the bullet from the case and drive it out through the bore?
The air gap between the power and the bullet is of less consequence. The idea behind a filler in more modern reloads is to get more consistent ignition. The gallery loads discussed is almost like a squib load. Is there sufficent power to genetrate the gases that will dislodge the bullet from the case and drive it out through the bore?
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So long as it's within the reloading book's limit. I don't like being a test dummy and neither should anyone else here.
hawg
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Black powder cartridges were designed to be filled up with powder.
Most of the discussions about gunpowders, be they black powder and smokeless, treat the combustion as if it was linear, like a candle. I have read enough on smokeless to know, combustion is not nice and linear, and what actually happens during combustion is beyond what my little mind can understand. I would assume that black powder needs to be compacted and dense to have a clean, smooth pressure curve.
A smokeless rocket motor class, the teacher talked about the interaction between acoustic and propellant pressure waves, and when they conflicted, the rocket went kaboom. I have read papers describing how unburnt propellants carried along at the front of a pressure wave, reflect pressure waves back at some ignition point, causing over pressure conditions. These papers were all based on computer modeling, and I am sure the models have been updated.
I did find this:
Cookoff of Black Powder and Smokeless Powder
https://www.osti.gov/servlets/purl/1784620
note at the end, while they were not looking for violence of explosion, the authors found some funnies during cook off. Maybe the powder partially combusted, and then, the rest went adding to the violence of the initial burn.
Conventional knowledge can be wrong, but I don't see any harm in compacting the charge of blackpowder, either in a muzzle loader, or cartridge case, as we have been taught. I always seated my Minies, round balls to the charge if I kept the barrel clean.
A smokeless rocket motor class, the teacher talked about the interaction between acoustic and propellant pressure waves, and when they conflicted, the rocket went kaboom. I have read papers describing how unburnt propellants carried along at the front of a pressure wave, reflect pressure waves back at some ignition point, causing over pressure conditions. These papers were all based on computer modeling, and I am sure the models have been updated.
I did find this:
Cookoff of Black Powder and Smokeless Powder
https://www.osti.gov/servlets/purl/1784620
note at the end, while they were not looking for violence of explosion, the authors found some funnies during cook off. Maybe the powder partially combusted, and then, the rest went adding to the violence of the initial burn.
Conventional knowledge can be wrong, but I don't see any harm in compacting the charge of blackpowder, either in a muzzle loader, or cartridge case, as we have been taught. I always seated my Minies, round balls to the charge if I kept the barrel clean.
hawg
Member
Black doesn't have to be compacted and dense. It just doesn't need any airspace between powder and bullet.
44 Dave
Member
I tried Cream O Wheat filler in .44 WCF. It works ok in a revolver, but ended up with a cooked mess the last 6", in the 23' barrel after the SASS match (50 rounds)
Would never even think of the trouble of using it a cap and ball gun.
Would never even think of the trouble of using it a cap and ball gun.
Ugly Sauce
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hawg
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Are you saying...that...you go "whole hawg" when you shoot?
You bet your sweet bippy I do.
Ugly Sauce
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I find much less smoke and fouling when well compacted/compressed. Of course it still goes boom, and spits the bullet out the barrel un-compressed.
I've tried for years to tell people pressure curves are not linear, and why just because a specific charge of smokeless, that produces the same overall pressure as a black powder load is not always safe, or the "same difference". (usually in discussions about shooting smokeless in the Trapdoor Springfield)
Carl N. Brown
Member
Slamfire said: I would assume that black powder needs to be compacted and dense to have a clean, smooth pressure curve.
That is the reason I was told for not having an air gap between between powder and ball/bullet in a black powder cartridge.
Consistent rate of burn. Consistent burn. Consistent velocity. .
I was not told an air gap between black powder and ball or bullet in a BP cartridge was dangerous.
I have been told that a smokeless powder charge in a BP rifle cartridge should be pressed against the primer with some sort of filler to avoid the powder charge being partially ignited, driven against the bullet base, exploding and sending a secondary pressure wave back to collide with the initial pressure wave. Sounded to me like the explanation of how RDX/Cyclonite "blows down" whereas blasting powder "blows up" when set off on a surface.
That is the reason I was told for not having an air gap between between powder and ball/bullet in a black powder cartridge.
Consistent rate of burn. Consistent burn. Consistent velocity. .
I was not told an air gap between black powder and ball or bullet in a BP cartridge was dangerous.
I have been told that a smokeless powder charge in a BP rifle cartridge should be pressed against the primer with some sort of filler to avoid the powder charge being partially ignited, driven against the bullet base, exploding and sending a secondary pressure wave back to collide with the initial pressure wave. Sounded to me like the explanation of how RDX/Cyclonite "blows down" whereas blasting powder "blows up" when set off on a surface.
woodnbow
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Dan Rowan and Dick Martin… “I didn’t know that!!”
Those were interesting times. I remember most of them, ....... sort of.
To keep it on topic, I think I'll continue to compress my black powder. I did learn something about fillers in bottleneck cartridges though.
whughett
Member
So what’s the explanation of why it’s ok in smokeless rounds but not with black powder. Just what happens to that air trapped in a cartridge case that differs between the two types of gun powder.
hawg
Member
Black powder burns at a consistent linear rate when its confined. When there's an airgap the flame can get ahead of the charge and make it explode all at once. Loaded in a cartridge it probably won't make any difference. Take some smokeless powder and make a trail out of it and light it. The flame just crawls down the length of it. Do the same with bp and it burns up right now. Smokeless burns the same whether it's confined or not. Compressed bp burns like the smokeless.
While I do want a controlled-burn/compressed column of BP as my 1st choice,
`splain why the original Sharps -- which cuts the tail off the paper cartridge to
spill back into the chamber and leave a considerable air space -- is not a problem?
hawg
Member
You got me. I wondered the same thing when I had my Sharps. My Sharps had a bigger chamber than most. It held 110 grains of loose Swiss 2F with a 490 grain ringtail. The factory recommended charge was 80 grains. That's a lot of airgap. The pamphlet that came with it just said to make sure the powder was touching the bullet but any airgap would turn it from a propellant into an explosive. I'm guessing with relatively small powder charges it wouldn't make any difference but get two or three inches between bullet and powder it would be a whole new ballgame.
hawg
Member
I didn't go to all that trouble. I just figured out how deep to seat the bullet in the cartridge so that 80 grains of powder came right to the edge of the breech. 80 grains worked best for me. With 90 grains it lost all semblance of accuracy. 100 grains was actually a bit more accurate than 80 but it had more flash from the breech block than I liked. When the cartridge was cut it lost very little powder. Once the cartridge was made I dipped the bullet in lube and slightly onto the paper. It looks like the air space is taken up by the cartridge but the cartridge is only the thickness of a couple of wraps of wrapping paper bigger than the bullet and the bullet was a sloppy fit in the chamber.
Cartridge seated in chamber,
Cartridge seated in chamber,
PWC
Member
Shooting was a lot more fun before I got involved in the science of it.
hawg
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RWMC
Member
Thank you for the excellent information that you provided in post. I happened to own a Frankford arsenal .45 caliber 4 cavity Roundball mould, like what you mentioned, and now I am going to have to try this! Good info sleepysquirrel2.
whughett
Member
I ask for a reason, that’s one explanation, although I fully don’t follow it.
A full load of black generates X amount of pressure. An air gap ahead of the burn increases that pressure enough to create a problem ??? The air gap adds energy. ??
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