Solid Shot Essentials: A Guide To The Authentic And Non-Authentic

Cast Iron Versus Steel: Authentic cannon balls and smaller solid shot (canister and grape) are made of cast-iron rather than steel. The Federal Ordnance Manual of 1862 stated that all shot and shell were to be fabricated from cast-iron with only one exception (lead).

How are they cast? The casting of solid shot and shell is well covered in Dean Thomas’ book Cannons. Basically, two hemispherical sand molds are prepared and are attached together. The mold-pair is filled from the side at the seam between the two mold halves until liquid cast iron appears in the mold’s vent at the top.

The casting process creates three distinct telltale identification points on cast solid shot that point to authenticity. These are:

(1)The mold seam created by liquid metal flowage into the tiny gap between the two mold halves;

(2)The filler hole sprue created at the mold seam from liquid metal entering the mold;

(3)The mold vent sprue created as the metal begins to fill the hole at the top of the mold. The vent sprue is always at a right angle to the plane of the mold seam.

The filler hole sprue is always located along the mold seam on cannonballs and is usually represented on the finished product as a small (0.25 to 0.50 inch) imperfection. If the cooling of the metal of the casting caused the metal in the vent to contract and create a depression in the casting this was sometimes patched with lead (rare).

Inherent in this type of casting is the presence of air bubbles being trapped inside the casting. This has the effect of weight reduction of the casting.