Black powder primer: Part 2
This report covers:
- The fineness of the grains
- Finer powder means faster ignition
- How airguns relate to black powder firearms
- Cannon powder
- White powder?
- Smokeless powder
In this report we continue our brief exploration into black powder. While this is not an airgun subject, it is airgun-related, as you will learn today.
The fineness of the grains
Black powder exists in a number of levels of fineness, from FFFFFg (5Fg) to Fg (1Fg). The F stands for fineness and the lowercase g stands for “graphited”, as in coated with graphite. I never knew 5Fg existed until I started researching this blog, but a company online actually sells it. I have always believed that 4Fg was the finest black powder that could be purchased.
Let’s relate black powder fineness to calibers. In rifles, muskets and cannons with barrels of .62 caliber and larger, Fg. is used. A starting load would be 1.5 grains of powder to each point of caliber. For a .62 caliber rifle 93 grains (1.5 X 62) would be a safe place to start. You work from that load up and down, searching for the best accuracy.
For a medium bore gun (.45-.61 caliber) use FFg powder. For a .54 caliber rifle you would use FFg powder and a starting load would be 81 grains (1.5 X 54).
For firearms smaller than .45 caliber, switch to FFFg powder and use one grain per caliber point. So, for a .32 caliber rifle, a charge of 32 grains of FFFg powder would be a good place to start. In some guns like cap and ball revolvers 32 grains might be too much powder to use because the ball must be rammed down on top of the powder in each chamber and the ball has to clear the breach so the cylinder will revolve. Firearms that are designed like that limit what can be loaded into them.
With black powder you don’t want any empty space inside the firearm or the cartridge. Empty space allows a pressure wave to build and it acts like a hammer as it passes through the gun. Black powder loads should always be compressed.
Finer powder means faster ignition
The fineness of the powder determines the speed at which it burns. The speed at which it burns determines the time it takes to rise to its maximum pressure and that, in turn, determines the calibers with which it can be used. Larger calibers have larger bullets, which means they resist moving more (longer) when the pressure rises.
Until discovering that 5Fg powder existed I would have said that 4Fg was the finest and fastest-burning of the black powders. It is used for priming the flashpans of flintlock firearms and for very specialized small-caliber black powder guns, such as .22-caliber derringers and so on. I suppose that 5Fg powder can also be used for these things, but having zero experience with it, I decline to say anything further.
How airguns relate to black powder firearms
I could make several points in this section about how the velocities of airguns and black powder firearms are similar — with the black powder firearms being limited to less than 2,000 f.p.s. and usually less than 1,400 f.p.s. I could also equate the power of black powder firearms to those of big bore airguns. While black powder elephant guns can develop over 5,000 foot-pounds of muzzle energy (a 4-bore gun shooting a quarter-pound (4-ounce or 1,750-grain bullet with 540 grains of black powder behind it), the type of black powder cartridges that most people shoot today top out at around 3,500 foot-pounds, with a lot of what we think of as the big boys, like the .45-70, stopping at around 2,000 foot-pounds.
Big bore air rifles are now up to around 1,000 foot-pounds at the muzzle, so there isn’t that much difference. But that’s not where I’m declaring airguns and black powder arms have crossed paths in a major way. No, I’m going back to the 1770’s when Bartolomeo Girardoni worked on a repeating black powder rifle.
Repeating rifles were unheard of in the black powder era until the self-contained cartridge came on the scene in the late 1850s. The danger of loose black powder being ignited in a repeater before it was safely inside the chamber was very great. When that happened, the gun blew up. Girardoni’s son was killed when his father’s prototype rifle blew his arm off. That was what led Girardoni to develop the repeating air rifle. His air rifle that the Austrian army adopted was .46 caliber and carried 22 shots in a tubular magazine that sat alongside the barrel and action. And I contend that if his black powder repeater hadn’t blown up he might never have developed his repeating air rifle of 1780.
The 1780 Austrian Girardoni air rifle was a 22-shot .46-caliber repeater.
Okay, we now understand the Fg system of powder fineness, but it doesn’t stop there. Powder granules also get larger.
There is a whaling powder that is used to fire the large harpoons used by whaling ships. Because the harpoons are heavier than cannon balls, plus they have heavy ropes attached to them, this powder has huge granules that approach a half-inch in diameter. Cannon powder exists in several sizes that are smaller than whaling powder but much larger than Fg powder. And I am not even addressing several specialized black powder granule sizes that are developed for specific purposes, such as life saving. Is that the powder that launches a ring life-buoy to a person in the water? I don’t know.
Black powder doesn’t have to be black. It’s the charcoal that gives it a gray color, plus the graphite coating on some types of powder. But throughout history there have been powders that were brown, white, yellow and even pink. It all depends on what they are made from.
For example, a mixture of crushed vitamin C tablets (ascorbic acid) and potassium nitrate (KNO3) makes a white, gold or pink powder that burns clean with little or no smoke and leaves water vapor in the bore. With this powder it is possible to shoot a gun clean! In the 1980s there was a company in Las Vegas that was trying to bring this kind of powder to market. It was to have been called Golden Powder, but from what I can tell it never came to market.
The advent of gunpowder made from nitrocellulose ended the high-level experimentation with black powder and related gunpowders. Nitrocellulose powder that we commonly call smokeless powder today is so much more powerful and controllable, that it eclipsed black powder in about 30 years after coming to market. The changeover was actually much faster than that, but black powder hung on for certain applications — both because it worked so well and also because the new smokeless powders had initial teething problems.
The military was quickest to recognize the advantages of smokeless and they pushed its development to get the velocity that extended the range of their rifles and machine guns. Black powder was left for the country boys who continued to use it even after smokeless proved to be better. It probably reached its lowest point in ther 1950s when Dixie Gun Works started promoting it to American sportsmen again. Know this — the .30-30 Winchester cartridge was the first popular smokeless rifle cartridge, and the second 30 in its name was to designate how much smokeless powder was contained in the case — just like the black powder cartridges had done (e.g the .45-70). That was the last big gasp of the black powder era.
This short series has been a quick look at black powder to address some things that some readers asked me to. As far as I am concerned, this is the final report. But if you have questions ask them and we shall see.
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