doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Chromed Bores

Great discussion, raising more questions.

I'd hate to think Brit gunmakers would avoid chrome with the idea of a future business in rebarreling....but you just never know.

Do top-line Italian guns (i.e. Fabbri) use chrome? Have heard that Perazzi does.

Just wondering why barrels, the "heart of the gun," wouldn't be made with the highest level of protection.

I did not wish to upset you folks. But built in obsolescence in user consumables is all around you TVs. Automobiles. Tools, I can remember when the simple screwdriver had just a straight blade but many sizes. But now look at the things more working ends than you can shake a big stick at, now a slotted wood screw on this side of the pond is classed as a restoration product. If gun makers could brain wash their customers to accept a guns life is ten years they would do it in a shot. Well Automobile makers and those fancy phone makers have convinced our youth that they need a new phone because the battery does not hold its charge as it did when new. But the SOBs are not fooling me for one minute to join in their let me sell you a new one old chap!!!

I�ve seen literally dozens of 700�s over the years with pitted barrels. Nothing special about 700�s in terms of barrel steel, it�s most definitely not seriously corrosion resistant.

Most Italian shotgun makers chrome line their barrels. I would hesitate to say all, because I have no proof of that. I wouldn't know about Fabbri, but my Texan friend, mel5141, shoots them and would know.

On another thought about it .............. it just seems to me that all plating is not done the same. The black chrome that some Turkish guns have on the outside of their barrels seems to be terribly different than chrome plating of car bumpers, color and surface finish aside. I cannot imagine what it would take to cause corrosion of any type on that finish. High humidity, fingerprints and sweat won't faze it. Maybe pure hydrochloric acid? I dunno.

I just know I have a lot more questions about chroming of barrels, inside and out, than I have answers. Still hoping to learn.

SRH

FYI, according to their website Fabbri guns have stainless steel barrels, and either stainless or titanium actions.

SRH

Much Chrome Plating is applied over a base plate of another metal. Back in the early 1960s, I was employed by a sporting goods maker in a Golf Club factory. I worked in the Iron Head department & became rather well acquainted with their plating process. I forget now just what the base metal was. may have been copper. Car Bumpers I am fairly certain use a similar process.

I will not argue the point as to whether or not plating is the proper term for shotgun bores, BUT I will say Emphatically it is NOT the same process used on car bumpers, nor on those Golf club heads. There is no undercoat to the gun bores & it does not peel or flake. Ruist does NOT build up under it, given the Wrong circumstances, it can rust through it, but does not rust under it. There is a difference.

You do not have to plate chrome over copper or nickel. Hard chrome in shotgun or rifle barrels is electroplated directly onto the steel bore. The plating is very thin.

Decorative chrome plating on things like car bumpers or motorcycle exhausts is typically plated over a much thicker layer of copper plating, or copper and nickel. The thicker plating fills in surface imperfections, and gives a smooth shiny surface without tedious labor intensive polishing of the basemetal. Shotgun or rifle bores don't need this because the internal finish is much smoother than something like a raw steel bumper out of a stamping die.

The relatively thick deposit of copper applied in a decorative chrome plating process also wouldn't hold up well in a firearm bore, and would cause a much greater reduction in bore size than a very thin direct plate of hard chrome only. It is necessary to make rifle bores slightly larger due to the slight reduction which occurs during the plating process. Especially with a rifle bore, it would be very difficult to maintain an even thickness the entire length of the bore if an under-layer of copper was applied. Naturally, such variations would cause problems with pressure and accuracy.

Keith covered it well. And hardchrome is definitely applied using the identical physics of electro-plating car bumpers. Car bumpers get "triple chrome plating" as Keith described, which is three different metals. The copper is plated thick so it can be buffed and flowed to form a smooth surface. The nickel plate provides the most corrosion resistant protection. The chrome is decorative. Hard chrome can be plated thin or built up. Airplane piston engines sometimes use the process to rebuild cylinders to original bore size by first grinding the bore oversized, then plating thick hardchrome, then grinding again, honing to final finish. It can flake off in thick applications , like decorative chrome, give similar conditions. I've seen neglected hardchrome cylinders flaking.

Either hardchrome or decorative chrome can be plated directly to the base metal. In the case of decorative chrome, either hexavalent or trivalent, it does not meet the needs of most products to directly plate decorative chrome on the base metal without the finishing aid of copper or the corrosion protection properties of the nickel.

Hardchrome and decorative chrome are not the same metal.

The gold, and other colored, coated drill bits, are a electro vapor deposition of nitrides or carbides, often titanium nitride. They are harder than hardchrome.

Both decorative chrome and hardchrome are deposited on the base metal by submerging the part and a piece of the metal which will become plating, into an electrolyte, and applying electrical current

Excellent, Keith and Chuck. Those were the explanations I needed to read to put the pieces together, and correct my errant thinking.

Your statement, Chuck, that hard chrome and decorative chrome are not the same metal is very enlightening. I may do some digging into that more, to learn the actual differences.

Thank you both for posting what you actually know about the process(es).

SRH