Using a barrel-steadying cradle of his own design and custom-made rifle barrels to shoot custom-crafted ammunition through a covered 200-yard tunnel, F.W. Mann spent the better part of 15 years studying the causes of bullet dispersion.
March 01, 2023
By Terry Wieland
Dr. F.W. Mann was a successful medical doctor and inventor, so much so that at the age of 37, he retired and turned his attention to his lifelong passion of discovering why bullets do what they do downrange, especially in terms of accuracy. His efforts culminated in publishing The Bullet’s Flight from Powder to Target: The Internal and External Ballistics of Small Arms; a Study of Rifle Shooting with the Personal Element Excluded, Disclosing the Cause of the Error at Target in 1909. The title of his book is a real mouthful, but the contents laid the foundation for today’s understanding of ballistics.
Franklin W. Mann was born July 24, 1856, in Norfolk, Massachusetts. He grew up on a New England farm and began shooting at the age of 12. He went on to graduate from Cornell University (1878) and the Boston University School of Medicine. He worked as a general practitioner for four years while running a shop where he sharpened knives and lawnmower blades. In 1889 he invented a machine for chopping slaughterhouse bones into bone meal for chicken feed. The money he made from the sales of those machines allowed him to retire from his medical practice in 1893.
By 1894 he had begun to devote his time and energy to discovering the causes that make bullets disperse when fired at a single point of aim. Working with members of the Massachusetts Rifle Association, including gunsmith/cartridge creator Adolph Niedner and barrelmaker Harry Pope, Mann started conducting experiments using custom-crafted rifle barrels and ammunition made to his specifications. Along the way, he invented a V-shaped, cast-iron, barrel-steadying cradle that removed the human factor and held rifle barrels as motionless as possible. At his farm, he constructed a massive concrete foundation to anchor the barrel cradles, and in front of the foundation, he built a 200-yard range where bullets could be fired through a cloth tunnel, which prevented wind disturbance. Stations within the tunnel held sheets of paper to measure bullet orientation and deflection at varying intervals.
His experiments resulted in an understanding of just how important bullet uniformity is for top accuracy. In fact, he concluded that a lack of bullet uniformity was the major cause of a bullet deviating from its intended flight pattern. He also concluded that uniformity in all loading components (including powder, brass, and primer) affected accuracy. We hold those principles to be true to this very day.
Interestingly, Mann was also studying bullet velocity (seeking to reach an incredible 8,000 fps) as well as muzzle blast. In his experiments, he used barrels as long as six feet and so short that the bullet protruded from the muzzle. He tested duplex loads, and he studied front ignition whereby he had cartridge cases made with interior tubes extending from the primer pocket to the shoulder. His idea was to direct the flame from the primer forward toward the upper end of the powder charge, beginning ignition there. According to one source, he had a million and one shooting ideas, and he spared no amount of time or funds to satisfy his curiosity.
Dr. F.W. Mann died at his home on November 14, 1916, at the age of 60. The barrel cradle he invented was adopted in 1920 by the National Institute of Standards and Technology and Aberdeen Proving Ground, and it has been widely replicated for studying ballistics. His book had been studied secretly by European combatants building the long-range artillery of World War I, and it has been a critical source of information for ballisticians for the last 110+ years.
