Navy Arms made some DBL shotguns that had chromed barrels. Is that who made your gun? It should appear on the barrels- either on the left side, the top or the bottom. You have to take the barrel out of the stock to read the proof marks, and see such markings on the bottom of the barrels.
Chromed barrels don't make the gun shoot better, but it surely makes the gun easier to clean. And, obviously, it protects the barrels from rust, provided the surface is cleaned, and dried properly. If the chrome is white, or "Hard Chrome", you can oil it, as you would any other steel to help protect it from corrosion. And, the outside of the barrels must be cleaned and oiled, as well as the locks, and nipples, butt plate, triggers, etc. I recommend that the nipples be removed after each shooting session, soaked in soapy water, while you clean the rest of the gun, scrubbed clean of BP residue, then oiled. The threads on both the nipples and the bolster where they mount need to be oiled lightly after they are cleaned and dried.
If this is an unfired gun, replace those nipples as soon as possible. The European-made nipples are notorious for failing, or being made wrong. Stick with Stainless steel, or the Bronze Alloy nipples from Ampco. I keep an old toothbrush in my kit to scrub nipples, and areas around the bolster on percussion guns. Pipe cleaners are used to clean, dry and oil the flash channel from the nipple to the chamber. :thumbsup:
Proving its chrome? Shine a light down the bore. If it shows a bright White in color its chrome- just like your car's bumpers. If its not chrome, the metal will look a bit more gray, than white. Any chemical test would damage the chrome, and you don't want that.
