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View Full Version : Why chrome lining?


Servo77
December 14, 2006, 01:09 PM
OK, I understand why military rifles are chrome lined, but you see a lot of shotguns featuring this as a selling point. Does it serve a purpose outside of corrosion resistance in a shotgun? Since shotgun ammo is non-corrosive, why is it necessary or desirable? Does it help with patterning?

Dfariswheel
December 14, 2006, 01:25 PM
Chrome lining of shotguns makes the bore less subject to corrosion and pitting, especially on guns used in bad weather or in saltwater bird hunting.

Another reason is, a chrome lined bore is much easier to clean, since lead and carbon fouling doesn't adhere to it as badly as in a plain bore.

mete
December 14, 2006, 01:28 PM
Eliminates corrosion, doesn't collect powder residue as easy , and easier to clean .

Servo77
December 14, 2006, 01:28 PM
does lead fouling cause corrosion?

skeeter1
December 14, 2006, 02:20 PM
I've got two shotguns with chrome-lined barrels. They shoot just fine, and a breeze to clean. No need for a bronze brush, just a patch with some Breakfree CLP and a wool bore swab, and they look like new. I like them alot.

Ruger4570
December 14, 2006, 09:17 PM
OK,, OK I am sold too :D

Dfariswheel
December 14, 2006, 10:07 PM
"does lead fouling cause corrosion?"

Not on it's own, but what happens is, moisture and fouling can work it's way UNDER leading and cause corrosion.

You never notice until you give it a good cleaning, then it's too late.

A chrome bore is really nice, but you can keep a standard barrel in like-new condition simply by cleaning it.
Use good, new scrub brushes like the "tornado" type to remove leading and fouling, and use a chamber cleaning brush to remove all plastic and carbon residue from the chamber.

miscusi
December 14, 2006, 10:08 PM
I ride motorcycle. Crusier types with the chrome on it where you sit up instead of bending over.. anyway the chrome plating on these are very fragile, and wears through.

How is it that the inside of a barrel chrome can last ?

( unless it is metallurgy where the chrome is IN the steel ) ? ? ? ? ?

mathman
December 15, 2006, 01:15 AM
I don't think that the chrome on a bike and the chrome in a barrel of a sg are the same type of chrome...I could be wrong. I know that a chrome lined barrel will not only prevent corrosion, but the life of the barrel is extended as well.

Crosshair
December 15, 2006, 03:30 AM
Does it have an effect on steel shot? Does it protect the bore from it?

mete
December 15, 2006, 06:12 AM
There are two types of chrome plating decorative or soft chrome and hard chrome .Hard chrome is much harder and more durable and that's what's used in the bore. Hardchroming an entire pistol is also done with hard chrome and is extremely durable !!....Steel shot is in a thick plastic cup so the shot never touches the bore. Even lead shot today is in a plastic cup.

Dfariswheel
December 15, 2006, 01:05 PM
The difference between hard and decorative chrome is:

Decorative chrome is applied by first copper plating the steel as a "base coat" then bright chrome is applied over that.
Look at this process as painting wood. Paint is ON the wood in layers.
The decorative chrome is in layers ON the metal, can crack, chip, and peel off, plus moisture can infiltrate BETWEEN the steel and the top layers.
This means that the steel can rust UNDER the chrome and you won't know it until the plating starts to bubble up and peel off like an old decorative chrome car bumper.

Decorative chrome, along with it's copper "primer coat" is a fairly thick coating, and since the layers allow the chrome to "give" when impacted, it would quickly flake off a shotgun bore.

Hard chrome is applied by a special process in which the chrome is applied directly to the steel, and actually "soaks" into the pores of the metal.
Look at this like a stain on wood. It's IN the wood.
Since the coating is bonded into the metal, hard chrome can't chip, crack, or peel, and since there IS no "between" the steel and the plating, moisture can't infiltrate under the chrome.
For this reason, hard chrome can't rust under the plating since there is no "under".
Hard chrome plating is exceedingly thin, and VERY tough and durable, since it uses the steel itself to support and toughen the plating.

However, the strength of hard chrome is directly related to the base metal it's applied to.
A soft metal will still be impact dented or scored, and if impacted beyond the capabilities of hard chrome it can chip.
This is why most platers won't process aluminum frames. The aluminum is simply too soft and will dent under the chrome.

For the same reason even chrome won't protect an older shotgun barrel made before steel shot, because it's made of a softer steel.
Newer guns made for use with steel have (usually) thicker, harder barrels.

mathman
December 15, 2006, 04:19 PM
I'm curious how expensive the hard chrome process is...and if it's not too expensive, why don't more manufacturers do it? I believe all Benelli and Beretta shotguns have the chrome barrel, but I'm not sure who else.