Barrels are effectively protected against wear by coating them inside with an armoured layer. This coating is done by centrifuge casting.

On special, proprietary systems the barrel, which is filled on the inside with the powdered hard-facing alloy, is heated to process temperature. The metal melt that is thus created applies itself, due to the centrifugal acceleration at high barrel speed, to the bore walls and hardens in this position. A extremely wear-resisting layer develops.