Cannon 3 is a cast iron 6-pounder, 7-feet in length (base ring to muzzle). The trunnions are slightly conical in shape with no visible foundry markings and are cast below the centerline of the tube.

Several features suggest that the gun was produced in Sweden. English guns typically have pronounced reinforces while Cannon 3 has a more angular, single-cone shape with the sides forming a nearly straight line from the vent field to the muzzle astragal. Likewise, the muzzle swell appears more angular in shape than the typical English tulip swell.

These guns are commonly called by the Danish descriptor "finbankers", a general term that describes a variety of Swedish guns. This gun was probably cast in Sweden most likely from c1675-c1700.

The only marks on the piece are a set of Arabic numerals crudely chiseled along the axis into the top of the first reinforced. These numerals: 1,7,3, and an unrecognizable cipher, may have been an "aftermarket" weight chiseled into the gun.