What is meant by breaking in a gun?
The term applies to firing initial shots with a new gun as recommended or after replacing the barrel. Breaking in involves firing a shot and cleaning the barrel, then firing another shot and cleaning the barrel again. You have to repeat the process until there is no more tombac residue left in the barrel. To check, stuff a cleaning cloth 2 cm into the muzzle. Afterwards you can fire three shots and then five shots several times, always cleaning the barrel between the rounds of shots. If the barrel is of high quality, fewer shots (about 10 to 20) are normally required. Thin jacket deposits near the muzzle do not affect performance.