A year ago, I toured CSM's operation and spent time in the bluing room. A cold rust bluing solution is hand applied to the barrels then the barrels are placed in a heated liquid tank.
I do not know what the cold rust bluing solution is used nor do I know what chemicals may be added to the distilled? water in the heated tanks. The barrels are periodically taken out of the tank and carted, recoated, and placed back in the heated tanks for further rust bluing. All of the CSM barrels are blued by this same process.
