Blackpowder to Pyrodex and Beyond
Although the term "blackpowder" is now convention, "gunpowder" was the term for many years. There was no other type of powder commonly used in firearms for over 500 years, so there was no need for any other designation. It was all blackpowder.
So, where did the wonder of blackpowder start? Well folks, there is no easy answer. The history of the invention of gunpowder is shrouded in mystery. Most sources suggest that blackpowder was developed in China in the early 800's. This is a reasonable best guess, but ancient Greece and India are mentioned as possible starting points as well.
Quite earlier, "Shooting powder" was mentioned in the writings of Julius Africanus, in the mid 200's AD. His full name is Sextus Iulius Africanus. All the dates of his life are uncertain. One tradition places him under the Emperor Gordianus (238-244) and another mentions him under Alexander Severus (222-235).
Roger Bacon (1246-1294), the prolific English friar, scientist, and philosopher mentions the explosive properties of saltpeter mixtures in his "De secretis operibus artis et naturæ", though he does not lay claim to the discovery. Though Roger Bacon was acquainted with gunpowder, it did not see general use in Europe until after his time.
Berthold Schwarz, a German monk, is sometimes credited with the invention of gunpowder, based on his improvements to the Roger Bacon formula. He took the name of Berthold in religion, to which was appended the adjective Schwarz (black), either on account of the color of his habit or because he was looked on as being addicted to the black art. It was in the course of his studies in alchemy that he discovered the explosive properties of gunpowder, which he applied to firearms.
The first to attribute it and its subsequent application to Schwarz appears to have been Felix Hemmelin (1389-1464) of Zurich in his "De nobilitate et rusticitate dialogus" (c. 1450). He states vaguely that the discovery was made within 200 years of the time of his writing. Many later writers, however, place the "friar of Freiburg" in the fourteenth century, and while some give 1354, the date inscribed upon his monument in Freiburg, as the time of his discovery, others simply give him credit for the invention of firearms and notably of the brass cannon. While it is perhaps impossible to determine with certainty whether he was the first to make the discovery of gunpowder, it is commonly admitted that the invention of firearms is due to him.
The first recorded use of gunpowder in firearms in Europe is a statement by St. Albertus Magnus (Albert the Great) in 1280 stating that gunpowder was used at the siege of Seville in 1247, referring to cannon. (See: A History of Firearms by Major HBC Pollard.) So, though we know of the involvement of many colorful people and places, the exact parentage of blackpowder is shrouded with smoke as dense as the powder itself produces.
Blackpowder is a mixture of 76% Potassium Nitrate (Saltpeter, KNO3), 14% Charcoal (Carbon, C), and 10% Sulfur (S). These were roughly the percentages, by weight, used by the U.S. Military in the mid 1800s. Sodium nitrate has been used in times past in place of the potassium nitrate. The ratio of the blackpowder formula has changed significantly over the years. Older English powder was 66.6 % / 22.3% / 11.1%, as made back in the mid 1300's. The mid 1600 French recipe was 75.6% / 13.6% / 10.8%.
It seems that hand-held muzzleloaders (hand cannons) became reasonably common by 1375 in Europe, used prior by King Edward II in 1327. The matchlock constituted the first mechanical device for firing a firearm, and was invented about 1440. (Source: The Age of Firearms by Robert Held.)
By 1470, the hand cannons had shoulder stocks. Progress continued, and none other than Leonardo DaVinci created illustrations of the wheel lock in 1508.
The flintlock is said to have been developed in France around 1600, and the Pilgrims landed at Plymouth Rock with wheel lock and flintlock arms in 1620. The flintlock became the dominant form of muzzleloader until the early 1800's.
Blackpowder burns rapidly. The charcoal serves as the fuel, sulfur is the binding agent, and the potassium nitrate is the oxidizer. See "The Chemistry of Blackpowder" in Sam Fadala's The Complete Blackpowder Handbook for more details.
Blackpowder is a comparatively inefficient powder. One gram of blackpowder gives you 718 calories of heat, 270 cubic centimeters of gas, and about half of a gram of residue. Upon ignition the sulfur burns, producing hydrogen sulfide, and the saltpeter decomposes, releasing free oxygen molecules, sustaining combustion, and combining with the carbon of the charcoal to form carbon dioxide and carbon monoxide. Heat energy is released as the gas expands. Sulfur will vaporize at 832.28º F. The principal gases formed are carbon dioxide, carbon monoxide, and nitrogen. About one third of the gas created is nitrogen. The solid products are potassium carbonate, potassium sulfate, and potassium mono- and higher sulfides, and carbon. The white smoke and fouling of blackpowder comprise the solids that are produced upon combustion. In one test, 82 grains by weight left 42 grains of solid residue. It should come as no surprise that about half of the fouling produced by blackpowder is typically left in a front-loader's barrel.
Blackpowder residue consists of potassium carbonate, potassium sulfate, potassium sulfide, potassium thiosulfate, potassium thiocynate, carbon, and sulfur. All the potassium compounds are salts, considered corrosive. The sulfides in the emissions create the nostril flaring rotten egg smell we all disdain.
By introducing moisture, the powder solidifies and could then be pressed into cakes. Further processing broke it into uniform grains by passing it through screens. This corning process, developed in the year1500 or so, was a major breakthrough in gunpowder technology. Corning is defined as "forming into grains."
Blackpowder is surface burning. Therefore, the holes in the screens controlled the grain size and the burn rate. Corning the powder made it safer to transport, the components would not separate out, the powder was easier to load in small arms, and it provided a significant increase in consistency. In 1860 Major Thomas J. Radman, a U.S. Army Ordnance officer (noted as the inventor of the copper pressure gauge), found that the rate of burn of blackpowder could be further controlled by compression. Burn rate was also governed by making the powder into larger or smaller compressed grains. The "Radman" grains were perforated so the hole/s increased their surface area while the outer surface decreased their area when burned.
Blackpowder as normally used produces relatively low pressure versus modern smokeless, so a large amount is needed. This larger weight increases the recoil of the firearm by adding to the ejecta. Free recoil is found in the SAAMI Technical Correspondent's Handbook Data Sheet #1.0401. It is mentioned here because a gun weight change alters free recoil on about a 1:1 ratio. Ejecta weight or ejecta velocity change alters free recoil on about a 2:1 ratio.
Longer barrels are required for proper combustion and the resultant gas expansion with heavier charges, contingent on grain size. Pressures have ranged from 5,000 psi for shotguns to 25,000 psi or so for rifles. The notion that blackpowder can "ONLY" produce low pressures is incorrect, as England's Able and Nobel were able to generate pressures of over 100,000 psi in their experimentation in the 19th Century.
Elephant Brand black powder (now sold under Schuetzen Powder, LLC) once made a FFFFFg (5F) grain size, the smallest known. FFFFg is the smallest popularly employed grain; it burns fast and was used primarily in handguns. FFFFg is considered flintlock pan powder. FFFg and FFg were a bit larger; they have long been used in rifles and shotguns. Fg was the largest: used in very large bore rifles.
By using under-oxidized wood in the powder, the aptly named "brownpowder" gave performance approaching that of the early smokeless powder. Brownpowder contained only 3% sulfur. This was essentially the last development in the blackpowder arena. Coming at the end of the blackpowder age, it was superseded by smokeless powder after a period of ten years or so, and fell into disuse after too short a period to make a lasting impression.
There were many intermediate powders prior to true smokeless; King's "Semi-Smokeless," "Dense Powder," and Winchester's "Lesmok" were among them. These were primarily combinations of blackpowder and nitrocellulose (guncotton).
Lesmok powder was primarily used in .22 rimfire caliber loads, with .32 caliber cartridges being produced as well. They produced much more smoke and fouling than today's modern smokeless loads; the fouling was substantially less than blackpowder, and the shooting advantage was that firing did not have to be stopped for cleaning, as with straight blackpowder. Lesmok powder was much less corrosive than were the straight smokeless loads. The powder charges were bulkier and tended to carry away more of the primer residue.
However, after the non-corrosive primer came into general use in .22 rimfire caliber ammunition, things changed. The salts left by the blackpowder portion of the Lesmok powder charge made it necessary to clean the bore soon after firing. Also, Lesmok powder was extremely dangerous to manufacture. By 1947, Winchester completed the last lot of Lesmok powder loaded for .22 rimfire caliber cartridges. Today, Lesmok .22 and .32 caliber ammunition is considered collectible.
The current standard in muzzleloading propellants is Pyrodex, manufactured by the Hodgdon Powder Company of Shawnee Mission, Kansas. There is a huge amount of product and ballistic information available at www.pyrodex.com. The late Daniel Pawlak and Michael Levenson invented Pyrodex. Dan Pawlak was killed in January 1977 when his powder plant exploded. The patent application was filed on July 25, 1975.
In part, the patent reads: "The advantage offered by our compositions is their unique property of imparting high velocity to a projectile within a firearm or the like without the concomitant development of dangerously high pressure within the chamber. It is known in the art that the muzzle velocity of a bullet or similar projectile leaving the barrel of a firearm is proportional not to the peak pressure developed within the bore, but rather to the integrated area under the pressure-time curve. Although the art has long sought propellant compositions which impart high velocities without the high pressure characteristic of smokeless powder, no commercially acceptable substitute for the well-known 'black powder,' without its inherent disadvantages discussed above, has heretofore been found."
The summary includes: "The compositions of our invention offer the advantages of being safer to handle and manufacture and producing more efficient propulsion to projectiles than do compositions in the prior art; that is, they tend to produce higher projectile velocities with lower pressures than compositions heretofore known." (See "Modern Pressure Measuring" by Dan Pawlak, Handloader Magazine, Volume 9, Number 6  PP 26 ff.)
Pyrodex can be substituted volume-for-volume for blackpowder. Pyrodex is classified as a flammable solid for shipping purposes, not as an explosive as blackpowder is. (In actuality, blackpowder does not explode in blackpowder firearms. There is a pressure curve.)
Pyrodex is more bulky then blackpowder so you can get approximately 30% more shots from it, pound for pound. Pyrodex is safer and cleaner then blackpowder, but still delivers a similar cloud of white smoke with each shot. Ballistically it duplicates blackpowder with less fouling. Even though Pyrodex fouling is less, it is still corrosive. Pyrodex is harder to ignite (600º F) than blackpowder and can produce gases at a temperature of 4000º F. Pyrodex RS grade is intended for muzzle-loading rifles and shotguns, P is for use in pistols, CTG is specifically for use in rifle and shotgun cartridges, and C is for use in muzzle loading cannons. (CTG and C grades of Pyrodex have been discontinued for some time.) Pyrodex "Select" grade is a very consistent grade powder for rifle and shotguns.
The Pyrodex preformed pellets currently offered have taken muzzleloading to a whole new level of convenience. The preformed pellet technology is not nearly as simplistic an achievement as the casual observer might think. It required great attention to compatibility of powders (blackpowder and Pyrodex), pellet density, and a center burn channel allowing for combustion not just from the breech outward, but also from the center of the pellets outward. All this, while still retaining the necessary controlled burn rates and pellet strength that prevent collapse of the cored cylindrical pellet during shipping, handling, and use.
G. Dean Barrett filed for his patented "Unitary propellant charge for muzzle loading firearms" on April 1, 1996. Other attempts at pellets have failed spectacularly due to a myriad of performance and consistency issues. An additional benefit of pellet use is the very consistent compaction level and moisture content, which is not easily duplicated with loose powder.
The latest and greatest in the blackpowder substitute category is Hodgdon's Triple Seven powder. A higher energy powder than Pyrodex, it provides for better velocities. Actually, Triple Seven gives not just higher velocities, but also less recoil due to substantial reduction of the mass of the ejecta. Remarkably, the "rotten egg" smell is gone as it contains no sulfur, and it cleans up readily with regular tap water. "Triple Seven" preformed pellets have been designed, tested, and currently have been released in .50 caliber, offering a higher level of blackpowder substitute performance.
Special thanks to both Chris Hodgdon of Hodgdon Powder, and blackpowder expert and author Sam Fadala for information included in this article. For further blackpowder reading, I can do no better than to suggest The Complete Blackpowder Handbook (4th edition) by Sam Fadala. Extra special thanks go to my friend and fellow scuba-diving enthusiast, Donna Cline (WebSite: aeroballisticsonline.com) for her help and encouragement.
Copyright 2003, 2012 by Randy Wakeman. All rights reserved.