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. 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, triggering rapid development of smokeless compounds which replaced brown powder.