How were guns manufactured?

Answer 1

The earliest guns were hand-made. Barrels were cast (later forged and drilled) and finished with hand files, stocks were carved from wood with hand tools.

Eventually, guns started to be mass produced in factories using the same techniques as any other machinery - milling, stamping, turning. Later automated machines came to be used for rifling barrels. There is also a special machine for mass-producing stocks that duplicates the shape of a single model on several pieces of wood at a time.