The barrel of a gun flint became a technological marvel, especially at that time. A blacksmith pounded a piece of flat iron to give cylindrical shape around a mandrel ( long stick diameter suited to what you want turning). Heating the iron in a forge to a certain temperature, the blacksmith caldeava groove along the length of the pipe to form a strong tube. This process could take days. The pipes varied from the length of a gun (15 to 30 cm) to the length of a big gun (102 152 cm).
The blacksmith could go inside the barrel finish with a flat cylinder or rifled barrel . A smooth cylinder is exactly that: a smooth rod tip to tip. The Brown Bess in the American Revolutionary War was "Smooth Soul", as well as any shotgun. It is made by sticking the tube with successively larger drills and then polishing it with a mandrel.
Raiar the barrel is a way to increase the accuracy of the projectile, whether spherical or conical. To dawn a pipe, you start with a plain cylinder, burilando spiral grooves inside the barrel. A common design is the curved rays at 122 cm in the length of the pipe. When the projectile is fired through the barrel, it fits in the rays, coming in a quick rotation (between 1000 and 3000 RPM) and flying at speeds ranging from 305-600 meters per second.
It can be seen rays spiral cut in the upper
Once the barrel was rifled or smoothed, one end is closed with a lock breech . After that, a small hole is made to allow the flame of the cartridge between the flintlock and light load.