Smokeless powder
Smokeless powder allowed the development of modern semi- and fully automatic firearms and lighter breeches and barrels for artillery.
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, and this problem became worse with increasing rate of fire.
Gunpowder burns in a relatively inefficient process that produces lower pressures, making it about one-third as powerful as the same amount of smokeless powder.
[6] A significant portion of the combustion products from gunpowder are solids that are hygroscopic, i.e. they attract moisture from the air and make cleaning mandatory after every use, in order to prevent water accumulation in the barrel that can lead to corrosion and premature failure.
These solids are also behind gunpowder's tendency to produce severe fouling that causes breech-loading actions to jam and can make reloading difficult.
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.
In 1871, Frederick Volkmann received an Austrian patent for a colloided version of Schultze powder called Collodin, which he manufactured near Vienna for use in sporting firearms.
Higher muzzle velocity meant a flatter trajectory and less wind drift and bullet drop, making 1,000 m (1,094 yd) shots practicable.
[9]: 141 The creation of cordite led to a lengthy court battle between Nobel, Maxim, and another inventor over alleged British patent infringement.
[4]: 146–149 Charles E. Munroe of the Naval Torpedo Station in Newport, Rhode Island, patented a formulation of guncotton colloided with nitrobenzene, called Indurite, in 1891.
Rather than paying the required royalties for Ballistite, Laflin & Rand financed Leonard's reorganization as the American Smokeless Powder Company.
The intent is to regulate the burn rate so that a more or less constant pressure is exerted on the propelled projectile as long as it is in the barrel so as to obtain the highest velocity.
The released heat, in case of bulk storage of the powder, or too large blocks of solid propellant, can cause self-ignition of the material.
[7]: 313 To neutralize the decomposition products, which could otherwise cause corrosion of metals of the cartridges and gun barrels, calcium carbonate is added to some formulations.
Alternatively diethylene glycol dinitrate (detonation velocity 6,610 m/s (21,690 ft/s), RE factor 1.17) can be used as a nitroglycerin replacement when reduced flame temperatures without sacrificing chamber pressure are of importance.
The first triple-base propellant, featuring 20-25% of nitroguanidine and 30-45% nitroglycerine, was developed at the Dynamit Nobel factory at Avigliana by its director Dr. Modesto Abelli (1859-1911) and patented in 1905.
In practice, triple-base propellants are, due to their higher price, reserved mainly for high-velocity large caliber ammunition such as used in (naval) artillery and tank guns, which suffer from bore erosion the most.
Although the slower reaction is often described as burning because of similar gaseous end products at elevated temperatures, the decomposition differs from combustion in an oxygen atmosphere.
Conversion of nitrocellulose propellants to high-pressure gas proceeds from the exposed surface to the interior of each solid particle in accordance with Piobert's law.
Energy is released in a luminous outer flame zone where the simpler gas molecules react to form conventional combustion products like steam and carbon monoxide.
Hot, combustible gases (e.g. hydrogen and carbon-monoxide) may follow when they mix with oxygen in the surrounding air to produce the secondary flash, the brightest.
[7]: 322–323 For artillery, the most effective method is a propellant that produces a large proportion of inert nitrogen at relatively low temperatures that dilutes the combustible gases.
[8]: 28 [3]: 41 The United States Navy manufactured single-base tubular powder for naval artillery at Indian Head, Maryland, beginning in 1900.
Similar procedures were used for United States Army production at Picatinny Arsenal beginning in 1907[7]: 297 and for manufacture of smaller grained Improved Military Rifle (IMR) powders after 1914.
Short-fiber cotton linter was boiled in a solution of sodium hydroxide to remove vegetable waxes, and then dried before conversion to nitrocellulose by mixing with concentrated nitric and sulfuric acids.
Nitrocellulose still resembles fibrous cotton at this point in the manufacturing process, and was typically identified as pyrocellulose because it would spontaneously ignite in air until unreacted acid was removed.
[3]: 28–31 Unreacted acid was removed from pyrocellulose pulp by a multistage draining and water washing process similar to that used in paper mills during production of chemical woodpulp.
"Lots" containing more than ten tonnes of powder grains were mixed through a tower arrangement of blending hoppers to minimize ballistic differences.
[28] Reworked powder or washed pyrocellulose can be dissolved in ethyl acetate containing small quantities of desired stabilizers and other additives.
The spheres can be subsequently modified by adding nitroglycerine to increase energy, flattening between rollers to a uniform minimum dimension, coating with phthalate deterrents to slow ignition, and/or glazing with graphite to improve flow characteristics during blending.
