The lock geometry is all wrong. The cock is too tall, and hits the frizzen too high up. The result is sparks that are gouged out of the frizzen, and literally are seen rolling down the face of the frizzen to dribble into the pan to ignite the priming powder. When the cock is at it forward, " rest ", position, you can see that the flint points way forward of the touchhole, instead of into the pan.

A good lock will throw the sparks in one stroke into the pan, either a little forward of the touch hole, or even with it. When the cock is rested, the flint will point to the center of the pan. The flint will strike the frizzen only a little above the half-way point of the height of the frizzen, providing the snap needed to open the pan. And, finally, the design of the toe would be such as to prevent the frizzen from rebounding and striking the flint. The second prupose of the feather, or frizzen spring, is to keep the frizzen in the open position after the gun is fired.