Smokeless powder

Smokeless powder is the name given to a number of propellants used in firearms and artillery that produce negligible smoke when fired, unlike the gunpowder or black powder they replaced. The term is unique to the United States and is generally not used in other English-speaking countries, which initially used proprietary names such as 'Ballistite' and 'Cordite' but gradually shifted to 'propellant' as the generic term. Smokeless powder is the name given to a number of propellants used in firearms and artillery that produce negligible smoke when fired, unlike the gunpowder or black powder they replaced. The term is unique to the United States and is generally not used in other English-speaking countries, which initially used proprietary names such as 'Ballistite' and 'Cordite' but gradually shifted to 'propellant' as the generic term. The basis of the term smokeless is that the combustion products are mainly gaseous, compared to around 55% solid products (mostly potassium carbonate, potassium sulfate, and potassium sulfide) for black powder. Despite its name, smokeless powder is not completely free of smoke;:44 while there may be little noticeable smoke from small-arms ammunition, smoke from artillery fire can be substantial. This article focuses on nitrocellulose formulations, but the term smokeless powder was also used to describe various picrate mixtures with nitrate, chlorate, or dichromate oxidizers during the late 19th century, before the advantages of nitrocellulose became evident.:146–149 Since the 14th century gunpowder was not actually a physical 'powder', and smokeless powder can be produced only as a pelletized or extruded granular material. Smokeless powder allowed the development of modern semi- and fully automatic firearms and lighter breeches and barrels for artillery. Burnt gunpowder leaves a thick, heavy fouling that is hygroscopic and causes rusting of the barrel. The fouling left by smokeless powder exhibits none of these properties (though some primer compounds can leave hygroscopic salts that have a similar effect; non-corrosive primer compounds were introduced in the 1920s:21). This makes an autoloading firearm with many moving parts feasible (which would otherwise jam or seize under heavy black powder fouling). Smokeless powders are classified as, typically, division 1.3 explosives under the UN Recommendations on the transportation of Dangerous goods – Model Regulations, regional regulations (such as ADR) and national regulations (such as the United States' ATF). However, they are used as solid propellants; in normal use, they undergo deflagration rather than detonation. Before the widespread introduction of smokeless powder the use of gunpowder or black powder caused many problems on the battlefield. Military commanders since the Napoleonic Wars reported difficulty with giving orders on a battlefield obscured by the smoke of firing. Verbal commands could not be heard above the noise of the guns, and visual signals could not be seen through the thick smoke from the gunpowder used by the guns. Unless there was a strong wind, after a few shots, soldiers using gunpowder ammunition would have their view obscured by a huge cloud of smoke. Snipers or other concealed shooters were given away by a cloud of smoke over the firing position. Gunpowder is a low explosive that does not detonate but rather deflagrates (burns quickly at subsonic speed). Gunpowder produces lower pressures and is about three times less powerful when compared to smokeless powder. Gunpowder is also corrosive, making cleaning mandatory after every use. Likewise, gunpowder's tendency to produce severe fouling causes actions to jam and often makes reloading difficult. Nitroglycerine was synthesized by the Italian chemist Ascanio Sobrero in 1847.:195 It was subsequently developed and manufactured by Alfred Nobel as an industrial explosive, but even then it was unsuitable as a propellant: despite its energetic and smokeless qualities, it detonates instead of deflagrating smoothly, making it more liable to shatter a gun, rather than propel a projectile out of it. Nitroglycerine is also highly sensitive, making it unfit to be carried in battlefield conditions. A major step forward was the invention of guncotton, a nitrocellulose-based material, by German chemist Christian Friedrich Schönbein in 1846. He promoted its use as a blasting explosive:28 and sold manufacturing rights to the Austrian Empire. Guncotton was more powerful than gunpowder, but at the same time was once again somewhat more unstable. John Taylor obtained an English patent for guncotton; and John Hall & Sons began manufacture in Faversham. English interest languished after an explosion destroyed the Faversham factory in 1847. Austrian Baron Wilhelm Lenk von Wolfsberg built two guncotton plants producing artillery propellent, but it too was dangerous under field conditions, and guns that could fire thousands of rounds using gunpowder would reach the end of their service life after only a few hundred shots with the more powerful guncotton. Small arms could not withstand the pressures generated by guncotton. After one of the Austrian factories blew up in 1862, Thomas Prentice & Company began manufacturing guncotton in Stowmarket in 1863; and British War Office chemist Sir Frederick Abel began thorough research at Waltham Abbey Royal Gunpowder Mills leading to a manufacturing process that eliminated the impurities in nitrocellulose making it safer to produce and a stable product safer to handle. Abel patented this process in 1865 when the second Austrian guncotton factory exploded. After the Stowmarket factory exploded in 1871, Waltham Abbey began production of guncotton for torpedo and mine warheads.:141–144