Chrome lined ML bore?

In reference to another post called "Inside the barrel" it got me thinking about the possibility and practacality of chrome lining ML bores. Without consideration of PC issues; I wonder if chroming the bore would effect cleaning procedures, add life to the firearm and maybe increase accuracy? Thoughts please?

 

[Dave K]

I beleive the Charles Daly made "Hawkens" of the 1980's had a chromed bore.

 

[No Deer]

My Pedersoli Mortimer 12 ga. shotgun is chrome lined. I clean it the same as all my other guns.

 

[paulvallandigham]

As I said before, I talked Homer Dangler into getting a barrel black chromed, years ago, and when I spoke to him the next year, he told me that while it didn't shoot any more accurately than a similar barrel without the chrome, it was much easier to clean. I have a revolver that is black chromed, and cleaning consists of running a bore brush with some lead solvent down the barrel once, then running a cleaning patch down, once, then running a second patch to confirm that the barrel has nomore lead, or copper, or powder residue in it! I inspect the barrel in good light, using a bore light, and have never had to do anything more to clean the bore. With Black Chrome you do not oil or it for storage. You leave it dry.

I had a Winchester shotgun with chrome lined barrels that required only a bore brush with solvent on it to remove the plastic streaks, and then a cleaning patch to take the plastic and solvent out of the gun. The barrels were done! The gun was used when I bought it, and the two men who had owned it and traded it back and forth were both competitive Trap shooters, who fire thousands of rounds through the gun every year. When I bought it, some bluing was missing, the stock had a few scratches, and one of the ejectors was bent, but the barrel looked like new. I shot the gun for many years putting probably another 5000 rounds through it, and when I sold it, it looked as good as when I bought it.

If you can get a barrel chromed, I would recommend it. The barrel has to be lapped before chroming, as the chrome only adds about 3 TEN THOUSANDs of an inch to the barrel. Its real contribution is in filling the pores in the steel so that crud can't get a foothold as well as it does in bare steel.

Having said that, I can't say you are going to get a more accurate barrel if you chrome the bore. I have shot barrels that were lapped that are so sweet to load you hate to shoot them. But when you do, you know you are holding a work of a master craftsman, and must treat the barrel with the utmost respect. They do shoot well. And, BTW, some of the barrels that come out of manufacturers are much better now than they ever were 50 years ago. I think competition has forced many gunmakers to improve the quality of the barrels they use and sell. Most barrels are more accurate than the shooter can hold them. Only neglect, and abuse ruins them, and that can be done with the best of barrels.

 

[Stubert]

I have a 58 cal. Investarms with a chrome barrel. 1-48 twist. It is fairly accurate, but it cleans like a dream, only 2 or 3 patches and its done. With the 1-48 twist I have to stay below 65 grains of 2f or the round ball strips the rifling and shreds patches. Minnies shoot good, but they beat you up with anything over 70 grains. The lightest one I have is 460 grains.

 

[paulvallandigham]

With that heavy a ball, you don't need more velocity. Glad you like the chromed bore. It does take cleaning to a different plane.

 

[cowpoke1955]

See what you started :rotf: . Happy birthday Paul! :grin:

 

[talon]

Navy Arms sold a few smooth bores in the late 80's early 90's with crome bores for use with steel shot.

 

[Mad Monk]

This is relative to the chrome lined Investarms barrels.

These were first imported by Sile back in the early 1980's. I was asked to look at one that had been blown up over in New Jersey.

Investarms electroplated chrome in the bores. Three applications (coats) of chrome.
They plug the breech end of the barrel to protect the threads holding the breech plug. The plug has a hole in the center that supports a rod in the center of the bore. The bore is then filled with chromic acid and an electrical current is applied. The bore then gets one coat of chrome. The "spent" chromic acid is removed and the bore refilled. Then a second coat is applied. The process is repeated for a third coat.

The down side. When the current is applied and run through the chromic acid it evolves hydrogen. The first coating process causes hydrogen to intrude into the steel beneath the layer of chrome applied. The second coating process also causes hydrogen to intrude into the steel but in a lesser amount. The third coat does not add hydrogen to the steel.
So the electroplating process will cause some hydrogen embrittlement of the base steel which in these barrels is rather soft.

You are applying layers of very hard brittle chrome over a soft steel base.

Every time you fire the gun there is a slight flexing of the steel barrel. But the chrome does not flex. As a result the chrome coating micro-cracks. If you look at one of these bores under a microscope you see the chrome cracked in a lozenge shaped pattern. You may then see rust forming on top of the tiny cracks.

The electroplating hydrogen embrittlement of the soft base steel and the pattern of cracks caused the cracks to extend down into the base steel.

All of this was observed under the microscope and followed descriptions given in texts on electroplating.

 

[paulvallandigham]

Obviously, the problem began with using soft steels for the barrels. I would hope the industry has learned from that. I still am not impressed with some of the steel used in some models of guns made in Europe and sold over here. The difficult part of all this is that the average consumer can't tell one steel from another. I have found that the general rule, " You get what you pay for " is currently the best guide in deciding which model of foreign made gun to buy, in that the higher priced imports tend to be made of better steels, and are machined and finished better. I do not have the same concerns about American Made firearms.

 

[Mad Monk]

Paul,

I had been getting an idea of how hard different barrels were by the difficulty in sawing when I would saw one from muzzle to breech plug with a hand held hacksaw.

Some of this business about how hard or how soft the steel is centers on what happens if a shooter blows one up. Soft steel barrels tend to bulge and split without blowing pieces all over the place.
The other school of thought is that if you make them hard enough they won't come apart.

Back in the days when Green Mountain first started up I spoke to Branch about his annealing process. He stated that he annealed more than enough to prevent fragmentation of the barrel. Kinda, big bulges before they split and or fragment.

I had sawn other Investarms barrels before I sawed open the chrome lined one. The hydrogen embrittlement of the steel was clear. A good bit harder than one from the same company that had not been chrome lined.

 

[Keppy]

Happy Birthday :thumbsup: Paul :hatsoff:

 

[paulvallandigham]

A look at the grain structure of steel barrels that have been cut or sawn is always instructive. I only wish we could set up such displays at every gun show, so that more people would be better informed as to what makes a good barrel and what doesn't. A little light acid wash over the end grain, to expose the grain structure, works wonders when you can show people the differences.

Barrel makers are also at the mercy of their suppliers. I spoke to a well known barrel maker in N. Central Illinois a couple of years ago, when I toured his plant, and he complained long and hard about the difficulty he had getting the quality of steel barrels he ordered. He had to have his testing down out of house, as he could not afford to have his own test equipment in the plant. He gave me a very good education on what his end of the business is like. He makes modern gun barrels, as his rifling machine will not cut the deep grooves required for ML rifle barrels. I asked.

 

[Mad Monk]

Paul,

I have decent photos of some of the barrels I sectioned for Dixon.

Nice photos of a patent breech from a gun not cleaned. Holes eaten through the plug. Something of a one of a kind as I have never seen another.

Then there is what I jokingly call the twice blown barrel. The chrome lined Sile Hawken from back in the mid-50's. The shooter parked the base of a maxi right over an under rib screw hole. The first short-start firing formed a little tear in the metal centering on the hole. The second time he fired a short-started maxi at the same spot the barrel came apart. Nice ring in the bore and bulged.

Then some photos of the pitted surfaces of my original GPR barrel that saw only bp and Wonder Lube.

I have two sections of barrels sitting on a shelf next to me with rings in the bore from short-start firings.

I had a bunch of other photos of burst barrels but they were from litigations and I had to destroy them when the cases were settled.
In these cases I looked at the barrels and simply pointed folks to who could best help them. I try to treat these law suits like a social disease.

If you would be interested in any photos for your work contact me by private message.

 

[TANSTAAFL]

Last year I picked up a used Sile (Distributors/importers) .50 percussion Hawken for the grand daughter, it has a chrome lined bore. I also bought a Sharps paper cartridge rifle back in the 1970's imported by Sile and it too had a chrome lined bore.

 

Great responses! But - with all that has been said, how would a person know that the bore in the ML was chromed?

 

[TANSTAAFL]

Great responses! But - with all that has been said, how would a person know that the bore in the ML was chromed?

If not black chrome, one look will tell ya, dull gray silver color.

 

[Mike Brooks]

I had an H. House .29 cal. rifle that was built in 1970 with a chrome lined bore. It shot great, but I never noticed it cleaned any different than a regular bore.