Brown Powder a.k.a. "Cocoa Powder"

Here's some excerpts from the Wikipedia article about Brown Powder.
It was basically made using a different type of charcoal that was not fully carbonized, making it brown.
The amount of sulfur was dramatically reduced, and the shape of the grains was more uniform.
It must have been shown to be an improvement when used in cannons. --->>> https://en.wikipedia.org/wiki/Brown_powder


Brown powder or prismatic powder, sometimes referred as "cocoa powder" due to its color, was a propellant used in large artillery and ship's guns from about the 1870s. While similar to black powder, it was chemically formulated and formed hydraulically into a specific grain shape to provide a slower burn rates with neutral or progressive burning, as opposed to the faster and regressive burn typical of randomly shaped grains of black powder produced by crushing and screening powder formed into sheets in a press box, as was typical for cannon powder previously.

Composition

The differences in burning rate were achieved by several means. Changes to formulation were altering ingredients relative percentage by weight and using differently processed charcoals for fuel than those of a standard 75:15:10 (potassium nitrate:charcoal:sulfur) black cannon powder.

Typically, sulfur was either not used in brown powders, or sulfur content reduced to around 1% by weight from the usual 10%. The reduction or outright removal of sulfur slowed the burn rate, while replacement of higher molecular weight sulfur dioxide by carbon dioxide or monoxide in the propellant gas mixture gave a higher specific impulse.

Differently processed charcoals were used. Fully carbonized charcoal (mostly composed of elemental carbon) in black powder provides its distinctive black color, while its replacement with an incompletely carbonized, brownish colored charcoal produces a dark brown appearance, hence the names "brown powder" or "cocoa powder". The less carbonized charcoal was more reactive than fully carbonized charcoal, somewhat making up for the easy ignition characteristics usually provided by sulfur. The brown charcoal also helped to produce sturdier grains and replaced sulfur in the role of a binder.

Further modifications of burn rate were achieved by shaping the individual powder grains, often into prismatic shapes such as single-perforated hexagonal or octagonal prisms.[1]

History

In 1884 the German Rottweil Company developed Prismatic Brown Powder (PBC), which was also adopted by the Royal Navy in 1884. It retarded burning even further by using only 2 percent sulfur and using charcoal made from rye straw that had not been completely charred. It was pressed into prisms with a central hole, similar to the 1.5 inches (38 mm) DuPont Hexagonal.

The French Navy instead developed the Slow Burning Cocoa (SBC) powder, which had grains of about 3.1 millimetres (0.12 in); still only 40% of it burned, the rest was ejected as heavy black smoke.

The first smokeless propellant, the guncotton-based Poudre B was introduced by the French Navy in 1886,[2] triggering rapid development of smokeless compounds which replaced brown powder.

I found a guy on youtube who posted 3 videos showing his 2 home made cannons being fired with his own home made brown powder.
The first video is 10:00 long and includes his early experiments with both the cannon and brown powder.
He explains that it creates less pressure yet will send a projectile 1/3 farther.
And he also explains that the brown powder charcoal is 50% carbon and 50% plant wood / cellulose which is the starting point for modern nitro-cellulose gunpowder development.



The caption for the 1st video mentions his formula.

"1-inch cannon & Homemade Brown powder (Also Prismatic or Cocoa) Gunpowder. Two recipes were uses for Brown prismatic Powders in the 1800s, 79% PN, 3% Sulfur, 18% Charcoal using wood Charcoal or 75% PN, 10% Sulphur, 15% charcoal using Rye Straw. ...

My Brown powder is 79, 3, 18 with Pacific Willow for Charcoal....."

The 2nd video is less than 3:00 long and shows his 2nd cannon.



His 3rd video is 3 minutes long and shows the same shots from his 2 cannons over and over in gradually slower slow-motion.

Dr. Charles E. Munroe in 1899 wrote:
... The more modern gunpowder, known as cocoa or brown prismatic powder... being compounded of 78 parts of potassium nitrate, 20 parts of charcoal, and 3 parts of sulphur... The brown prismatic grains for the United States Navy guns measure [about an inch in both diameter and height and are perforated by about a 1/3" hole or canal for ignition]. The advantage which this brown gunpowder possesses over the black is that it is less brisante, and that, therefore, a higher velocity may be imparted to the projectile without bringing an undue pressure upon the walls of the gun.

It is, however, not only slow-burning, but also difficult of ignition, and it is therefore necessary to press grains of similar form and dimensions from the quicker burning and more easily ignited black powder, and to place a number of these ignition grains in the base of the cartridge which is to be placed in contact with the primer in the breech block of the gun.

An absurd situation grew out of this necessary adjustment at an official exhibition [of a recently mounted gun] at Fort Washington, on the Potomac, a few months ago... On the second round the magnificent weapon was elevated and the order to fire given, but without effect, and after investigation it was ascertained that the failure was due to the cartridge bag [that is, the black powder] having been reversed in loading the piece.

... A marked disadvantage, and one which recent events have strongly impressed upon the public, is the smoke which it produces when fired, more than 50% of the total weight of the powder charge being thrown out as solid matter to foul the atmosphere, becloud the gunner, and make his situation a conspicuous target for the enemy.

Many smokeless powders are now known and used... [written in 1899 by Dr. Charles E. Munroe for "High Explosives In Naval Warfare", pp.115-116 of Cassier's Magazine, an Engineering Monthly, Volume 15] --->>> https://books.google.com/books?id=XU_OAAAAMAAJ&pg=PA115&lpg=PA115&dq=mixing+black+gunpowder+and+cocoa+gunpowder&source=bl&ots=fuuU2OOA2A&sig=2Kqe5fzCAV5_UdqyD-Z-nmNMEo4&hl=en&sa=X&ei=ZBqHVaHtHMG9ggSxroGABQ&ved=0CB0Q6AEwADgK#v=onepage&q=mixing black gunpowder and cocoa gunpowder&f=false

Brown or red charcoal is a charcoal that is made by under-burning organic material. The material used for producing this charcoal was rye straw. The straw was piled into large stacks and stored in open air for long periods of time, the stalks being large and thick, with the ears of rye removed from it. Then, the straw was placed in large wrought-iron chambers and superheated steam was pumped over the straw for several hours. The temperature of the superheated steam was carefully controlled. The superheated steam would dissolve most of the extractive matter from the straw, but would not char it fully and the result was a charcoal of a reddish or brown color (in French, this was called charbon roux). We studied about this charcoal production process using steam earlier. --->>>
http://firearmshistory.blogspot.com/2016/09/brown-or-cocoa-powder.html

Using steam to produce charcoal: --->>> http://firearmshistory.blogspot.com/2016/06/historical-manufacture-of-charcoal-ii.html

Using hydraulic presses to form prismatic "powder pellets" --->>> http://firearmshistory.blogspot.com/2016/09/black-powder-xxiii-prismatic-powder.html

Imagine that Cocoa powder is sold in Russia for the purpose of mixing it with black powder.


He is not mixing smokeless powders. I do not understand Russian, but I think that black powder is on the left, and slow-burning cocoa powder (a.k.a. brown or prismatic powder) is on the right. It is more powerful than black powder, but it also burns slower and requires significant back-pressure for it to become explosive. Think mid-1800's cannon powders. I think that the Russian wants less strain on the gun, more velocity, and more uniform pressure down the barrel. He appears to have mixed them about 25%-75%, with an empty pistol cartridge and a cut-down shotgun shell. He is loading slugs.

I found on eBay the directions in Russian on the back of an identical can of this brand of cocoa powder.



http://www.shotgunworld.com/bbs/viewtopic.php?f=2&t=423269

Various sizes and pieces of gunpowder.
An engraving depicting various sizes and pieces of gunpowder, in use towards the end of the nineteenth century, ranging from the fine Poudre-brutale (1) through pebble (2) mammoth (3) prismatic (4) to cube (5) which could weigh half a pound and have 2 inch sides to each cube. Dated 19th century. (Photo by: Universal History Archive/Universal Images Group via Getty Images) --->>> https://www.gettyimages.com/detail/...ous-sizes-and-pieces-of-news-photo/1077564586


Below: Sizes and Shapes of Powders.—In fig. 1, a to k show the relative sizes and shapes of grain as formerly employed for military purposes, except that the three largest powders, e-f-g and h are figured half-size to save space, whereas the remainder indicate the actual dimensions of the grains. a is for small-arms, all the others are for cannon of various sizes. --->>> https://en.wikisource.org/wiki/1911_Encyclopædia_Britannica/Gunpowder

HMS Colossus 1882 - 1906

Cocoa powder pressed into prisms is referred to as ‘Prism, Brown’, and this is the type of powder carried by HMS Colossus for her 12 inch Mk IV rifled breech loading guns.

A still slower burning powder was needed as guns increased size to 13.5 and 16.25 inches. Slow-burning Cocoa (SBC) was adapted from Prism, Brown by small alterations in its composition.

Colossus battering charge

The full charge for one of Colossus’ 12 inch guns is 295 lbs of Prism, Brown. This ‘battering’ charge, used when firing against armour, is made up of four cartridge bags made from silk cloth, each holding 73.75 lbs of Prism, Brown powder. If great penetrating power is not required, such as when firing against unarmoured ships, then a reduced or ‘three-quarters’ charge is used – three cartridges. For general practice a half charge would be used.

Silk bags are used since this material is entirely consumed when the cartridge is fired, otherwise a burning residue could be left which might cause a premature explosion when the next cartridge was placed in the gun. --->>> http://www.victorianshipmodels.com/colossus/gunpowder.html