The Damascus Barrel
Damascus or "Damascus twist" barrels are older shotgun barrels that typically were made before 1900. Iron and steel ribbons were twisted and welded together. Damascus barrels are weaker than modern barrels and are not designed for the high gas pressures created by modern ammunition. Damascus barrels have a distinctive, irregular pattern of short, streak-like marks around the barrel.
If you have a Damascus barrel gun, don't shoot it. The barrel may burst slightly ahead of the chamber, crippling the shooter's hand or forearm. If you have an older firearm and are not sure if it has a Damascus barrel, go to a qualified gunsmith to identify its make before shooting it.