Abstract: A computer numerically controlled apparatus is provided for rifling a gun barrel. The apparatus automates the known method of rifling a gun barrel. The apparatus includes a frame, a rod, a cutting tool, a rod holder, and a system of servos to move the rod holder and to rotate the rod. The apparatus includes a CPU runs a program which controls the servos based on operating parameters entered by the operator. The operating parameters are entered through a graphical user interface which also allows the operator to monitor the status of the rifling process. The operator can calibrate the system and enter the twist rate, number of grooves, cut degree, cutting speed, return speed, and number of passes to complete. The apparatus includes a puck which engages the end of the rod and is adapted to index the rod and change the cutting depth of the cutting tool.