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Quantifying Friction Effects of Molybdenum Disulfide, Tungsten Disulfide, Hexagonal Boron Nitride, and Lubalox as Bullet Coating.

ADA568594

Publication Date	2012
Personal Author	Boyle, P.; Humphrey, A.; Courtney, M.
Page Count	5
Abstract	Molybdenum disulfide (MS2), tungsten disulfide (WS2), hexagonal boron nitride (HBN), and Lubalox are common bullet coatings that purportedly reduce friction between the bullet and rifle barrel. Three different bullets, one a solid copper design, and two jacketed lead bullet designs, were tested in the 5.56 mm NATO rifle cartridge. After coating, these bullets were test fired through a chronograph with powder charges ranging from 0.52 grams to 0.91 grams. The energies of these bullets along with a control group of uncoated bullets were plotted against the powder charges. The work of friction for each combination was then determined as the vertical intercept obtained by least squares regression to a line. The different coating and bullet combinations produced changes in friction ranging from reductions in friction of 15% to increases in friction of 19%. Given the time and expense of coating bullets, the reduction in friction is not cost effective for most applications.
Keywords	Boron nitrides Chronometers Molybdenum compounds Small arms ammunition Tungsten compounds Coatings Copper Cost effectiveness Costs Gun barrels Interception Least squares method Regression analysis Rifles Solid phases Sulfides Test and evaluation Vertical orientation Lubalox Armor penetration Brass Full metal jacket Steel penetrator Bullet coatings
Source Agency	Non Paid ADAS
NTIS Subject Category	99D - Basic & Synthetic Chemistry 79A - Ammunition, Explosives, & Pyrotechnics 79G - Guns 71E - Coatings, Colorants, & Finishes
Corporate Authors	Air Force Academy, CO.
Supplemental Notes	The original document contains color images.
Document Type	Technical Report
Title Note	Research rept.
NTIS Issue Number	201311

Quantifying Friction Effects of Molybdenum Disulfide, Tungsten Disulfide, Hexagonal Boron Nitride, and Lubalox as Bullet Coating.

Quantifying Friction Effects of Molybdenum Disulfide, Tungsten Disulfide, Hexagonal Boron Nitride, and Lubalox as Bullet Coating.
ADA568594

Publication Date	2012
Personal Author	Boyle, P.; Humphrey, A.; Courtney, M.
Page Count	5
Abstract	Molybdenum disulfide (MS2), tungsten disulfide (WS2), hexagonal boron nitride (HBN), and Lubalox are common bullet coatings that purportedly reduce friction between the bullet and rifle barrel. Three different bullets, one a solid copper design, and two jacketed lead bullet designs, were tested in the 5.56 mm NATO rifle cartridge. After coating, these bullets were test fired through a chronograph with powder charges ranging from 0.52 grams to 0.91 grams. The energies of these bullets along with a control group of uncoated bullets were plotted against the powder charges. The work of friction for each combination was then determined as the vertical intercept obtained by least squares regression to a line. The different coating and bullet combinations produced changes in friction ranging from reductions in friction of 15% to increases in friction of 19%. Given the time and expense of coating bullets, the reduction in friction is not cost effective for most applications.
Keywords	Boron nitrides Chronometers Molybdenum compounds Small arms ammunition Tungsten compounds Coatings Copper Cost effectiveness Costs Gun barrels Interception Least squares method Regression analysis Rifles Solid phases Sulfides Test and evaluation Vertical orientation Lubalox Armor penetration Brass Full metal jacket Steel penetrator Bullet coatings
Source Agency	Non Paid ADAS
NTIS Subject Category	99D - Basic & Synthetic Chemistry 79A - Ammunition, Explosives, & Pyrotechnics 79G - Guns 71E - Coatings, Colorants, & Finishes
Corporate Authors	Air Force Academy, CO.
Supplemental Notes	The original document contains color images.
Document Type	Technical Report
Title Note	Research rept.
NTIS Issue Number	201311