Stray Rounds: 19th century gunpowder

Jeffrey Edel
U. S. Park Ranger
Historic Weapons Supervisor
Castillo de San Marcos National Monument

Notes from the Historic Weapons Program Manager

Ideally gunpowder converts completely into a gas upon ignition to push a projectile out of the barrel of a firearm with maximum force.

The black powder in use until the late 1800s transformed less than half of itself into gas.

Close to 55 percent remained in the weapon after firing as a clinging black fouling.

Successive layers from each round steadily reduced the effective diameter of the bore, and clogged the barrel’s vent hole and coarted the flint and frizzen surfaces.

A pick and brush or a rag could be used to clean the exterior lock areas but the accumulation of fouling inside the bore meant that after less than a dozen firings a tight-fitting lead ball could become lodged part way down the barrel when rammed (with
the danger of rupturing the breech if fired in that position).

So the longer it was used in battle the less reliable a flintlock musket became as fouling built up.

Closing quickly with the enemy and engaging in hand to hand fighting was therefore a necessity because of the limitations of black powder firearms.

(Adapted from: Neumann, Battle Weapons of the American Revolution)