It is a ramrod from a Kammerbüchse. The format and position of the numbers and letters below the head of the ramrod are consistent with Austrian Army regulations of the period. It was the 15th Kammerbüchse assigned to the 3rd or 8th ____ ____. I don't know what "C.N." stands for. Matching marks should be found on the left breech forward of the chamber section and on the top of the butt plate. From your photo it looks like the head was shortened by 1/4 - 1/3 of an inch; perhaps because it was damaged or to reduce its weight. You didn't need to smack the ball to expand it into the rifling grooves in a shotgun. Austrian practice called for it to be made of steel.
Regards,
Don Dixon