Musket balls are one of the earliest forms of bullets that are fired from muskets and rifles. Their origins date back to the 15th century, when “handgonnes” were first being used. Archaeologists and metal-detecting enthusiasts have discovered them all over the world. In the U.S., musket balls are most often associated with the Revolutionary War but are found on sites ranging from the first Spanish expeditions to the American Civil War.
Musket Ball Construction
These early bullets typically were made of lead or lead-tin alloys, following this standard process: The lead is melted and poured into a two-part mold, down a channel in the mold called a sprue. After the lead solidifies and the ball is removed from the mold, the sprue is cut from the musket ball with a cutting tool, which leaves some of the casting sprue and a snip line in the lead, called a medial ridge, caused by the cutter. Usually the mold also leaves traces of the mold seam around the circumference of the ball.
Feel the weight
Hold the ball in your hand. Lead is a very dense metal, and a musket ball will feel heavy for its size when compared to something like a glass or clay marble.
Check for surface characteristics
Look for evidence of a mold seam. Because of the crudeness of some 18th-century molds, the seam of an authentic musket ball may be slightly offset like the one in the photograph above. Look for evidence of a casting sprue made from the inlet channel of the mold. The lead from the channel is usually clipped off using a sprue cutter and leaves a medial ridge on the sprue. Note: not all musket balls have an obvious casting sprue mark.
Look at the color
Examine the ball for a patina. Authentic musket balls are not shiny gray lead. Musket balls buried underground for years develop a coating of lead carbonates, sulfides and oxides. This coating is usually white or light tan. However, the presence of tannic acid from trees or high levels of iron oxide in the soil can darken the color of an authentic musket ball to a deep reddish-brown.
A gray-colored ball with a blistery surface may be authentic, but it was molded from an alloy of lead and pewter or lead and tin. This was a common practice used by the American army during the American Revolutionary War, since lead was in short supply.
Measure a round ball
If the ball is round, measure its diameter in inches with a set of calipers, but do not take the measurement on the mold seam. Typically, musket balls range in diameter from 0.39 inches to 0.80 inches. The British Brown Bess musket had a 0.75 inch bore but took a 0.693-inch-diameter ball. Charleville-style French muskets, which were supplied to the Continental Army, had a 0.69-inch bore but took a 0.63-inch ball. Rifles took smaller balls, measuring less than 0.60 inch in diameter but usually no smaller than 0.39 inch. Lead balls with diameters of less than 0.39 inch are usually buckshot.
Weigh a misshapen ball
If a musket ball is not spherical, measure its weight in grams using a scale with at least 0.1-gram accuracy. Calculate the ball's diameter with the Sivilich Formula:
Diameter in inches = 0.2228 x (Weight in grams)1/3
(This is the cube root of the weight in grams.)
The result will yield a reasonable approximation of the original diameter of the musket ball. Alternatively, you can download the Sivilich Formula calculator (in a downloadable Excel file) to find the estimated original diameter of a musket ball using its weight.
Archaeologists have discovered authentic musket balls that were severely misshapen for a variety of reasons, but typically balls were misshapen from being fired and hitting a target.