Henri-Gustave Delvigne

Delvigne addressed this problem by producing a rifle chamber smaller than the bore, with which it was connected by a spherical surface equal in radius to the ball used.

[2] According to the artillery historian John Gibbon: "Delvigne, by placing a chamber at the bottom of the bore of an ordinary rifle, and making use of it to force the ball, dropped loosely into the bore, did away with the great objection to the use of rifles in war, the difficulty of loading them, and gave an impetus in regard to investigations about the arm, which has created a perfect revolution in the system of arming infantry, by leading to the present efficient weapon.

[5] Delvigne's invention was further improved by the French officer Thouvenin, who induced the deformation of the bullet by placing a stem inside and at the center of the powder chamber.

When hit by the ram, the bullet would expand radially against the rifling grooves and at the same time wrap around the stem, giving it a more efficient and aerodynamic shape.

[6] These inventions mark important steps in the improvement of the rifle, and are precursors to the Minié ball, to whose development Delvigne contributed.