François Tamisier

Captain Tamisier obtained a patent in 1841 for a method to improve the accuracy of cylindro-conical shot, by cutting three sharp grooves (French: "cannelures") on the cylindrical part of the shot.

[1] Compared to round shots, which offered a rather inefficient but symmetric and stable aerodynamic round profile, the aerodynamic stability of the cylindro-conical shot had been an issue in early rifled weapons of the type developed by Delvigne.

The Tamisier grooves greatly improved the efficiency of the cylindro-conical bullet.

However they rendered the forcing of the bullet against the grooves of the rifle bore in the Delvigne system rather difficult.

This provided for a progressive forcing of the ball as it moved through the barrel, greatly improving its efficiency.

Tamisier grooves ( "Cannelures" )
Cylindro-spherical (left) and cylindro-conical bullets (middle) developed by Delvigne , were improved with stabilizing bullet grooves developed by Tamisier
Tamisier grooves in a Minié ball
Before Tamisier's invention, the orientation of a cylindro-conical bullet would tend to remain along its inertial axis, progressively setting it against its trajectory and increasingly meeting air resistance, which would render the bullet's movement erratic.