The Minie ball, the bullet most identify as the weapon of mass destruction in the civil war, bears the name of French Army Captain Claude -Etienne Minie. He is generally credited with solving the problem of using expanding gasses to force portions of the bullet into the rifle groves. Others improved upon his design.
Amongst other attributes in the minie-ball’s design are the unique rings formed into the body below the conical shaped head. These rings accomplished two tasks: first to minimize friction within the bore of the rifle musket and second to provide guidance once in flight. The cylindrical shape is a departure from the previous musket bullet – the ball. This shape allowed the minie-ball to exit the bore of the rifle musket tube in a linear fashion. The design of the base allowed the gasses, derived from the explosion of the 60 grams of gun powder, to force the bottom end of the bullet into the rifle groves in order to spin. This spin tended to improve the accuracy of the bullet, much the same as a quarterback throws a football. The second element to improve guidance is the rings. These corrected any tendency of the bullet to wobble in flight. This was accomplished by increasing the resistance to air flow if one portion of the bullet were to yaw left or right along the flight path of the bullet. The bullet would be forced back to where the resistance in the air was minimized. See C. Wilcox, p. 130-134 for a more technical explanation http://books.google.com/books/about/Rifles_and_Rifle_Practice.html?id=JNtEAAAAIAAJ
This innovation, use of the rings, was discarded soon after the civil war because it substantially increased air resistance and contributed to its reduction in range and the shape of its trajectory – the parabolic arc. The minie-ball, due to its relatively low muzzle velocity, was more pronounced the farther one attempted to shoot. This natural phenomenon is due to gravity. Air resistance means the bullet flies slower and gravity pulls it down. Jack Coggins in his book Arms Equipment of the Civil War, drew the bullet path as follows, likening it to a rainbow.
More precisely, the tail end of its flight is a more pronounced, downward path and therefore shorter. From this diagram, you can see that the dangerous space as Wilcox termed it occurs at the beginning and end points of the bullets’ flight path.
For my purposes, this will alter what I termed the danger zone. One of the first clear models of this was a blog by 67thtigers. http://67thtigers.blogspot.com/2010/05/ballistics.html.
His drawing, reproduced below demonstrates the high parabolic arc of the minie-ball.
In this graph, ground is in light blue at the bottom. The purple horizontal line represents the height of the top of one’s head. The musket rifle is aimed at three different ranges; 100 yards, 300 yards, and 500 yards. These coincide with the three preset sight apertures provided on the Springfield rifle musket. The height in inches, relative to the firers’ muzzle, is provided along the left axis. It is easy to appreciate the challenges to a civil war soldier hitting his target. Doc White described the problem this way. http://www.whitemuzzleloading.com/long_range_muzzleloading.htm
“Firing at a target 225 yards away with a Springfield is difficult; you must set your sights at 300 yards, and then aim below the targets feet, awkward when poorly trained soldiers naturally shoot high. The solution adopted for the line infantry of the US, CS and also most of continental Europe was to set sights at 100 yards, and only shoot at 150 yards or less”.
Given this understanding of the problem of the parabolic arc, I searched for software that would assist me in plotting the impact in the swale as experienced by both confederate and union soldiers during the battle of Fredericksburg in December 1862.
My next blog will show the results.