New techniques for understanding 17th century siege warfare

 

Reconstructing the maximum possible diameter of a spherical bullet using the bowl of an impact scar from St Luke’s church, Holmes Chapel (image: Dr Paul Bills, University of Huddersfield).

I came across this 4-year old article on the English Civil War. It's interesting, though a bit technical.

New archaeological techniques, however, are beginning to provide more scientific explanations of how 17^th century warfare was fought. In this guest post Amanda Wynne from the University of Huddersfield explains how laser scanning technology is helping us to more accurately interpret English Civil War sieges - and the benefits the results may have for other fields ...

I wish they had included a scale with this picture. But based on my estimate of a Nikon lens cap, that is a damn big scar on this chunk of sandstone.

 Experimentally produced bullet impact scar from a 12 bore musket ball.

So how big is a 12 bore musket ball?

Well 12 bore means that 12 lead balls the diameter of the barrel would weigh 1 pound. So 1 musket ball weighs 1.33 ounces. For those of you from the post Napoleonic world, that's 37.8 grams. You don't want to get hit with that even if the muzzle velocity is only 400m/sec.

The article on Gauge (bore diamater) in Wikipedia gives provides formula to calculate the diameter of the ball. 

• Divide 453.59 (grams in 1 pound avoirdupois) by n to find the mass of each one of the balls.
• Divide it by 11.34 (density of lead) to find the volume of the ball.
• Multiply it by 0.75 and divide it by pi, then find its cube root, (rearranged from the volume-of-a-sphere equation) to find its radius in cm.
• Multiply it by 2 to find the diameter in cm.
• Divide it by 2.54 to find the diameter in inches.

Crunching the numbers yields a diameter of 4 cm or nearly 1.6 inches! They certainly had big balls back in the day.

${\displaystyle d_{n}=1.67051437/{\sqrt[{3}]{n}}}$