Gun Metals

An

an account of the metals used in firearms

from the earliest days

James Kelly

DE ROERMAAKER, 1736

COPPER ENGRAVING BY LUYKEN, 1736

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Wrought Iron, Steel & Cast Iron................................................ 5

Wrought Iron ........................................................................ 5

Steel ...................................................................................... 6 Oriental Damascus Steel ....................................................... 9

Layered Steel ...................................................................... 10

Pattern welded ("Damascus") Steel .................................... 10

Blister Steel ......................................................................... 10

Cast Steel ............................................................................. 13

Cast Iron .................................................................................. 17

Copper Alloys ........................................................................... 19

Bronze ................................................................................. 19

Brass.. ................................................................................ .22

German Silver ..................................................................... 24

Pewter ..................................................................................... 25 Tin .......................................................................................... 26

Silver ...................................................................................... 26

Old English & French Measures .............................................. 28

Old Chemical Names .............................................................. 28 ©2013 James Kelly Rochester, Michigan First written August 21, 2007, corrections & additions 3/9/09, 3/18/10, 3/25/12, 8/13/12, 8/19/12, 8/30/12, 8/5/13, and 10/18/13. Published on-line in "Arms Heritage Magazine" Vol. 4 No. 1, February 2014, www.armsheritagemagazine.com

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Introduction Metals of one sort or other have been used for at least 14,000 years. The history of hardened steel goes back three thousand years in the Middle East. In Ancient times mankind knew only seven metals. These were gold, silver, copper, tin, lead, mercury and iron. Each was associated with a heavenly body: gold with the sun, silver with the moon, iron with the Mars, mercury with Mercury, lead with Saturn, tin with Jupiter, and copper with Venus. Later zinc and antimony were recognized, though there weren’t enough planets to fit them into the heavenly scheme. . . The first metallic alloying element intentionally used in iron or steel was nickel, discovered at the end of the 18th Century. The terms used to describe metals, and their heat treatment, are ancient, and come from that time when there were just seven of them. Our modern usage of terms such as iron, steel, brass, anneal, etc. rarely means the same thing as it did in the 18th or early 19th century.

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Wrought Iron, Steel, and Cast Iron

Wrought Iron “Wrought iron cannot be cast, and cast iron cannot be wrought” was the ancient view of these metals. Pure iron is an element, with the chemical symbol Fe, from the Latin word for iron, ferrum. It is magnetic, and not very strong. Iron has little commercial value in its chemically pure form, and is usually seen mixed with, or alloyed with, some other elements. The nearest thing to pure iron one might commonly find in the hardware store is “black iron wire”, typically 1008 steel. That is, mostly iron with 0.08% carbon by weight. The first iron used was meteoric iron, which contains a few per cent of nickel. Tutankhamen had one dagger forged of meteoric iron, and another of gold. At the time the two metals may have been comparable in value. The oldest form in which iron was refined from ore is called “wrought iron”. This term means just what it says, that it is iron which has been wrought, or forged, into shape—it is not cast iron. Wrought iron is fairly pure metallic iron mixed with maybe 3 percent by weight of slag fibres. This slag is a glass made of iron oxides, and calcium silicates. It runs through the iron as long stringers. It is lighter than iron, so that 3% by weight means more than that by volume. If you look at an old piece of rusted wrought iron you will see a “grain”, or long lines, on the surface. Those long, stringy marks are from the slag fibres, which did not rust.

Old wrought iron bar found around the Great Lakes This slag has a positive effect on the properties of wrought iron. One is that when wrought iron is brought to a forging heat, glowing white hot, some of the slag melts on the surface and acts as a flux. This permits two pieces of wrought iron to be readily forge welded together. Herodotus says the art of welding was discovered by Glaucus of Chios. Indeed, for nearly three thousand years forge welding was the only kind of welding.

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Then about a century ago a process was developed to “weld” steel by melting an iron wire into the joint. Since that time the word “weld” has meant a process of joining two pieces of metal by melting the edges, as well as melting a metal wire (the “weld rod”) into the joint. However, all welding used in the production of a muzzle-loader was done by forge-welding.

Since modern steel, by whatever name, lacks this slag, the modern blacksmith may sprinkle a flux on his hot iron to aid in forge welding. The presence of these slag fibres also gives wrought iron a grain, rather like wood. That is, across the grain it is more likely to break, just like a wooden board. When wrought iron is forged into a part, like a Colt revolver frame, care is taken that the “grain” runs in the way that the part will have the most strength. If you closely examine firearms of the Civil War and earlier you may sometimes marks, or seams, from these slag fibres. They show in Spencer rifle frames, which were wrought iron, and sometimes in Colt revolver frames, made of Norwegian wrought iron. Confederate revolvers sometimes used wrought iron, instead of steel, for cylinders. They twisted that iron to increase the bursting strength of the cylinder. The spiral lines on many Confederate revolver cylinders are from slag in the wrought iron.

slag

Colt Navy Brevete

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The marks on the case-hardened frame of this Navy Colt Brevete are from slag in the wrought iron. The frame forging was in an “L” shape, and the slag lines roughly follow around the corner of the “L”.

close-up of frame

Marks like this on an old gun indicate either that it is an antique made of wrought iron, or that it is a very well-thought out fake. I once saw such slag marks on an “antique” tomahawk, then later realized it was an investment casting, with “slag lines” cast right into it.

The last American made wrought iron was puddled in 1961. It is wonderful stuff for the blacksmith but unfortunately must now be located piece by piece, from antique scrap.

The master, right, taps the place where his helper is to strike a heavy blow, with both hands. Farrier’s tools haven’t changed in five centuries. Der Schmidt, Jost Amman 1500’s

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For centuries gun barrels were made by forge-welding a skelp of wrought iron into a tube, boring, reaming and straightening. The process for rifles is well described by Captain John G. W. Dillin1, The Kentucky Rifle, and by Walter Cline2. Great detail of musket barrel manufacture is given by Merritt Roe Smith3.

While the slag makes wrought iron relatively easy to forge weld, hand-forged welds are not terribly reliable. The failure rate in proof of hand forged barrels at Harpers Ferry arsenal was in excess of 25%, and sometimes exceeded 40%. At Springfield Armory water-powered trip hammers provided a heavier, more consistent blow to effect the weld. Barrel loss in proof at Springfield was down around 8-12%3. I understand that the older generation of muzzle-loading shooters, in the 1930’s, preferred wrought iron barrels. When I was younger, and still immortal, I used to shoot 19th century wrought iron pieces. After perhaps twenty years as a metallurgist I got around to looking at (what passed for) welds in wrought iron barrels. With all respect, you can have them. Mine will stay on the wall. Unfortunately that is not to say that some modern muzzle-loading barrels are any better, due to poor choice of steel. One common choice, AISI 12L14, has very low ductility, about 8% across the grain, with low impact properties4. This steel has good tensile strength, but does not well tolerate seams or other flaws. Now & again this costs someone a hand.

Steel Steel is, for the most part, iron with some the addition of up to 2% carbon. Carbon, that black element we most commonly see as soot or lamp black. Reasonably pure iron, such as wrought iron, cannot be hardened at all by heat treatment. It is the presence of carbon that permits this metal to be hardened by heating red hot and quenching in water or oil. Hardened steel is used for springs, knives, axes, swords and other tools. Names have different meaning today than in older times. The metal commonly called "steel" today, like steel nails, I-beams and auto sheet metal does not have enough carbon to harden, and did not exist in olden times. Let us start with steels used for swords and daggers. Three types are the Oriental, or authentic, Damascus steel; layer welded steel; and pattern welded steel. That last one is commonly referred to as "Damascus" steel, when it is used for shotgun barrels of the 17th through early 20th centuries.

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To digress, the first steel tools were most likely forged from iron meteorites. I believe the words for “steel” in various languages have the same root as the word “star” in those languages, as steel came from the stars. The Egyptian King Tutankhamen was buried in 1352 B.C. with two daggers of precious metal, one being gold, the other iron. The value of those two metals may have been comparable, at that time. His 13-3/16” dagger was made of iron with about 3% nickel in it. The nickel content means that it is most likely of meteoric origin. The sheath is of gold. from www.eternalegypt.org

Oriental/Authentic Damascus, Layered Steel, and Pattern Welded Steel5

Authentic, or Oriental, Damascus Is also called "wootz", the Indian word for "ingot". Over perhaps two thousand years this steel with the "watered pattern" has become the stuff of legend. It was made by melting wrought iron in a clay crucible, with charcoal or leaves added to get the carbon content up very high, 1-1/2 to 2% carbon by weight. Until the land trade routes were closed by the Arabs even the Vikings made some swords of this steel. It became known in Europe as Damascus steel. There are different opinions regarding the origin of this name. One is that fine swords and knives were made out of wootz in the Islamic world, and Damascus was an important trade center on the route between India and Europe. The steel blade below shows the pattern known as Mohammed's Ladder, or Kirk-Narduban, produced by a special forging technique.

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To bring out the pattern the steel blade is polished, then etched with mild acid to bring out the pattern in the steel itself. Acid darkens the steel, but leaves the coarse iron carbides lighter. Different forging techniques can make elaborate patterns, including one known as Mohammed's Ladder. Production stopped in the mid-nineteenth century for various reasons. One may have been depletion of the iron ore deposits in Hyderabad, India.

Layered Steel This Indonesian Kris is made of "layer-welded steel". Layers of different types of steel, both low and high carbon, were forge welded together. The forging was cut in two pieces, piled up and forge welded again, sometimes several times. After the blade had been forged to shape and polished, etching showed the pattern where the different grades of steel met. Some of the iron or steel involved may have contained a little nickel, which will be less affected by the acid. Today the etching is still done, in Indonesia at least, with a piece of citrus fruit and a bar of "warangan" , an Asian name for a mineral high in arsenic trioxide (As2O3).

Pattern Welded Steel This is what we see in old "Damascus" barrel shotguns, such as this 8 gauge Tryon used for market hunting on the Chesapeake Bay. Barrels were made by twisting together rods of low carbon wrought iron and high carbon steel, then forge welding them to combine the ductility of soft iron with the strength of steel.

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Steel—Blister Steel (cementation steel) and Cast Steel Blister Steel Because wrought iron has very little carbon, it will not harden when heated cherry red and quenched in water. Wrought iron makes good horseshoes and gun barrels but it is useless for knives, swords, axes and other cutting tools. It must have a decent amount of carbon in order to harden. Steel, in the old terminology, is the element iron with a certain amount of carbon in it, typically from about 1/5th of a percent up to maybe 2%. It is the carbon that permits steel to become hard when it is heat treated. There have been a number of ways to make steel through the ages, but for the most part only two were used for the antique guns in your collection. The first process was “cementation”. Long flat bars, or “skelps”, of wrought iron were packed in a large box, with charcoal all about them. The box was closed up, sealed with fireclay and heated bright red hot for about a day. At this high temperature carbon from the charcoal gradually “soaked” into, or diffused into, the iron. This kind of process was, and still is, referred to as cementation. When the steel maker thought it should be about finished he would withdraw a test bar and quench it in water. Then he broke it, to see the “depth of steeling”. If the bar had absorbed carbon all the way through, it would become very hard all the way through from quenching. When broken, the fracture would be bright and crystalline in appearance.

If the process was not quite finished there would be a soft, low carbon center to the bar. When broken, that part would appear fibrous, and different than the hard steel “case”.

As carbon diffused into the bar it reacted with the iron oxide in the slag. Carbon reduced these oxides to metallic iron. The process gave off carbon monoxide gas. That gas raised blisters on the bar surface, hence the product was known as “blister steel”. It was the lowest grade of steel made. The carbon content was highest on the surface, and lowest in the center. In order to use blister steel at all, one needed to at least forge the blisters shut. The next better grade was “shear steel”. Blister steel bars were sheared in half, bundled together and forged to make “shear steel”. Forging the bundle down to a new skelp made the high and low carbon layers thinner. But, the metal still was not of uniform chemistry, and it included the same slag stringers that were in the original wrought iron skelp.

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The Democratic Expounder, Marshall, Calhoun Co., Michigan, February 21, 1851

The frizzen spring of this Italian snaphaunce has a long seam, caused by the ever-present slag in the steel of that time. It is not the fault of the locksmith, nor is it a crack caused by long usage. It was there from the beginning. It might not have been noticed until time, and some corrosion, accentuated it.

A flintlock frizzen is forged of soft wrought iron. In order for it to spark, the surface must somehow be hardened. Frizzens (hammers, more correctly) of flintlocks were “steeled” by forge welding or brazing a piece of steel onto a wrought iron part. When that steel wore out it could be replaced by another piece, brazed on.

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I examined two original American flintlock rifles and a Ryan & Watson brass barreled pistol, all three with a flat piece of steel brazed to the iron hammer. On the Ryan & Watson the steel is about 40/1000” (1 mm) thick. Military arms and better English pistols show no braze line, so it seems reasonable to assume the steel was forge-welded to the wrought iron back. The whole thing might have been lightly case hardened when finished. It would have been very impractical, in my opinion, to case carburize an entire wrought iron frizzen deeply enough to be useful. On wrought iron, deep carburizing generates carbon monoxide, which raises blisters. This distorts the metal & requires forging to weld these blisters shut.

American flintlock rifle, late style, with a piece of steel nearly 1/16” (1.5mm) thick brazed onto the frizzen. The rifle itself shows very little signs of use, so this might have been done when the lock was made. Capt. John G.W. Dillin illustrates this same rifle, from the Clarence St John collection, as No. 3, Plates 93 & 94.

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Cast Steel Acier Fondu

The first thing any gun collector should know about cast steel is that “CAST STEEL” stamped on a gun barrel absolutely does not mean that it is a casting. It was the 18th & 19th Century way of describing a metal that we would just call “mild steel, carbon steel, or high carbon steel”. In the early 18th Century a watchmaker named Huntsman in Sheffield, England was dissatisfied with the shear steel available for mainsprings. It was not uniform in properties, so that the mainspring delivered erratic power to the gear train. In turn, the watch was not so accurate.

With knowledge gained from potters in the area, Mr. Huntsman developed a process to make steel of uniform quality, that is, having the same carbon content throughout. What he did, in 1744, was to place short pieces of blister steel in a crucible. He then used advanced furnace technology from the potters to heat that crucible hot enough to actually melt the steel. That required heating the metal to around 2700—3000°F. It was the first time in the Western world than anyone had ever melted steel. Once pieces of blister steel melted, the carbon mixed uniformly throughout, and molten slag floated to the surface. Huntsman poured his crucible full of molten metal into a mold—he “cast” it—to make an ingot. Then the ingot was reheated, and forged down into a bar of desired size or shape. Because the steel was actually melted and poured into a mold, it was called “cast steel”, to distinguish it from blister steel. Melting steel and pouring it into an ingot was quite an advance in technology for Europeans. Of course, our Indian associates would remind us that the famed Wootz steel, or true Damascus steel, had been produced by the crucible process in India for perhaps 20005 years. Wootz was a very high carbon steel, not uncommonly about 1.7% carbon. 18th century Englishmen paid high prices for a razor forged of Indian "Damascus" steel.

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English cast steel of the 18th century was iron with about 1% of carbon in it. Various carbon contents, which they called “tempers”, were available. This steel was used for knives, swords, axes—in short, all manner of cutting tools. Circular saws in the 1866 city directory for Detroit were advertised as “Cast Steel Saws”, or “WM. JESSOP & SON’S ENGLISH CAST STEEL SAWS”.

High carbon steel like this is strong, but it is not ductile enough for a gun barrel. As time went on, the English learned how to make a lower carbon cast steel, a “decarbonized steel”. This metal, very roughly similar to a modern AISI 1040 or 1060 steel, could be used to make gun barrels. In the US this lower carbon cast steel was first used in pistols. Steel barrels were used by Allen in his Pocket Rifle (underhammer pistol) by 18376. All of the Allen & Thurber pistols I have seen have been marked “CAST STEEL”. Samuel Colt used steel for the cylinders and barrels of his revolvers. Originally he may have used American steel, but by about 1850 he was getting steel from Thomas Firth, of Sheffield, England7. Eventually “cast steel” rifle barrels came into more common use, either bored from solid or rolled out from a pierced billet to have a rough hole already in them. Ned Roberts8 describes these and opines that those bored from solid shot better.

The major 19th Century supplier of barrel blanks to the gun trade was Remington. Quite a number of rifles may be found stamped REMINGTON on one or other of the flats near the breech. Remington supplied barrels, locks, and mountings, only. To my knowledge they did not make complete percussion rifles, their name simply indicating the source of the barrel.

Breech end of barrel on a W. Robinson rifle, stamped REMINGTON

Remington supplied barrels to the trade at least as early as 1825. Possibly at this early date they may have been wrought iron, and not steel, barrels. The account book of Alvin D. Cushing, gunsmith of Troy, New York, has survived and is in the Historical Society, Troy, New York. Courtesy the late H. Jerry Swinney, I saw that this book had notations for October, 1825 which read: to 7 rifle barrels Remington $21 1 burst barrel $1.50 1 burst barrel $1.50 14 rifle barrels $42.

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Four different stamps have been observed on Remington barrels9 P & S REMINGTON REMINGTON REMINGTON CAST STEEL

The earliest, according to S. James Gooding, is the semicircular form, found on Canadian rifles circa 1834-1841. P & S REMINGTON was found on two Canadian rifles from about the 1840’s through the 1850’s. Marcot10 notes that P & S REMINGTON stands for Philo & Samuel Remington, who were in business about two years, beginning about 1843. REMINGTON was found on a Canadian rifle dated 1840—1850, on a William Robinson rifle made in Mt. Clemens, Michigan some time after 1857, and on a rifle by H. F. Palmer, active in Michigan approximately 1862—1878. REMINGTON over CAST STEEL may be slightly later. Other contemporary sources for rifle barrels include a barrel forge in Mott’s Corners, southeast of Ithaca, New York. This may be the same forge which H. Jerry Swinney noted was operated by Lull & Losey, northeast of Ithaca. Another company, Hitchcock & Muzzy, later Muzzy & Co., of Worcester, Massachusetts, also supplied steel barrels to the trade.

This barrel is on a half-stock target rifle by C.L. Cone, HITCHCOCK & MUZZY

made somewhere in New England. It came to me from CAST – STEEL Vermont.

Through the first part of the 20th Century tool steels were melted in small crucibles, and the product was known as “crucible steel”. Around 1850—1860 Whitworth’s Fluid Compressed Steel became available in England, as well as Bessemer steel. When I examined the microstructure of a Fluid Compressed Steel rifle barrel, it appeared to have about 0.35% or so carbon, and was annealed.

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In all cases the steel barrel was much stronger than wrought iron, and did not contain the weak zone caused by the weld. However, any steel may contain defects, and even modern steel rifle barrels must be magnetically inspected for seams, then proof tested in addition. Few contemporary manufacturers of muzzle-loading rifle barrels bother with such niceties. Such barrels may be comparable to, at best, mid-19th Century standards of safety and reliability.

Until just after our Civil War the best Cast Steel came from Sheffield, England. Not only did the English have skilled & experienced workmen, they also had long term contracts for the best grades of Swedish charcoal-smelted finery iron made. American importers got Swedish iron considered “second mark” or “common” in Sheffield. In addition the clay used in Sheffield for crucibles, Stourbridge clay, had superior properties for deoxidizing the molten steel at the final stage before pouring into the ingot mould. American cast steel of consistent quality was not made until the 1860’s. It was developed to serve the Collins Axe Company, who disliked the erratic response to heat treatment of American made steel at that time.

Cast Iron—Gray and Malleable

Gray Iron

Gray cast iron is the traditional brittle cast iron of which frying pans, old iron stoves, engine blocks and cannon shot were cast. It is called gray iron because when it is broken the fracture surface is gray in color, from all the graphite flakes in the metal. Gray iron has no ductility when loaded in tension, nor can it be bent. Muzzle-loading cannon of gray cast iron were used, but did eventually blow up. Gray iron was ideal for explosive shells. Fragment of a cast iron 11 inch shell, delivered to Fort Fisher, North Carolina, C.S.A., January 15, 1865 by the Federal fleet under Captain Kidder Randolph Breese.

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Malleable Iron This is a form of cast iron which has some degree of ductility. It was commonly used for pepperbox frames, nose caps of US muskets and other parts where resistance to repeated shock was not required.

During the Civil War when demand for revolvers was high, Remington began making revolver frames of cast malleable iron, rather than forged wrought iron. The military11 asked Remington to go back to wrought iron. It is not clear that they did so. One such malleable iron revolver, later converted to cartridge for the U.S. Navy, is shown below.

Malleable cast iron was developed in the early 18th Century by a French man, de Réaumur12. He was looking for a process to make decorative iron fences and gates without the labor intensive process of hand forging each piece. They could be cast of gray iron, of course, but the result would be too brittle to handle well without breakage.

Now, if gray iron is made with insufficient carbon, or freezes quickly in the mold, it becomes extremely hard, too hard even to grind, and brittle. When broken the fracture is bright and shiny, which is why this type of cast iron is called “white iron”. Réaumur found that annealing this white iron for a day at red heat, 1750°F, eliminated the brittleness, and gave the metal some amount of ductility.

Thick sections in castings may have shrinkage voids form during solidification. This Remington Navy had the recoil shield machined away in the process of converting it to cartridge. Shrinkage in the casting is now revealed, about in the center of where the recoil shield had been.

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When Colt established his London operation he decided to make the trigger guards of iron, rather than brass, to suit the British preference. Like the brass guards used in America, the English trigger guards were cast. In Colonel Colt London, Joseph Rosa states that “At first, the guards were so brittle that they snapped like glass when they were taken from the moulds. But it was later reported that “after having undergone the annealing, they became so tough that they will bear hammering out, or may be bent into any irregular shape. . .” This is descriptive of malleable iron. When cast it is white iron, which is exceedingly brittle. After annealing for a day it becomes “ferritic malleable” and has some reasonable ductility.

Copper alloys—Bronze, Brass and German Silver

Bronze The first copper alloy used in history was arsenic bronze, followed by tin bronze about 5000 B.C. in the far East. The weapons Homer speaks of in the Iliad were all of tin bronze. Roughly speaking, you may consider bronze to be an alloy of copper and tin, while brass is an alloy of copper and zinc, and German silver is a mixture of copper, zinc and nickel. The SAE in 2004 listed over 500 different alloys, whose names include various combinations of the words copper, brass and bronze. The alloying elements used now cover the alphabet from the most ancient, Arsenic, to the newest, Zirconium.

You might find it useful to remember the differences amongst tin bronze and brass, copper and gilding metal. They are all different shades of red and yellow. Nickel silver is nearly white. This name is often confused with a similar alloy called German silver, which has a slight yellowish cast to it.

Bells are made of bronze with about 22% tin and 78% copper. This makes a fairly hard alloy with a good ring. This hard metal may also crack if the bell is hung wrong. You may recall a famous bell cast in Philadelphia which cracked when rung quite vigorously. If one is to melt down church bells to cast cannon, one must add some copper to the melt so the metal is ductile enough for a gun. “Because of its particularly sonorous quality, bell metal, containing from 20% to 24% tin, is used for casting bells.” Church bell of Sienna, A.D. 1159 hwww.msu.edu/~carillon/batmbook/chapter4.htm

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This 12-pound Napoleon, at Rock Island Arsenal, was cast of a 90% copper, 10% tin alloy13. The weathered surface has pattern, from the large cast grains and the fine, needle-like structure of a tin-rich phase. More tin would increase tensile strength, but at the expense of toughness.

One can sometimes tell the difference between a weathered piece of tin bronze, and a like piece of brass, or brass with a little tin, by appearance. Brass castings do not have the fine pattern caused by tin, all one can see is the individual grains. You may see this on brass door handles outside public buildings, which have been polished and etched by years of handling. Many alloys, called variously brass or bronze, are alloys of copper with both tin and lead. One such is cast Gunmetal, also known as Government Bronze G, with the Unified Numbering System identification C90500. The alloy is nominally 88% copper, 2% zinc and 10% tin. In practice a little lead may be added to improve the soundness of the casting, and for machinability.

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Analyses of this Sharps 4-barreled pistol, .30 rf model 2-A, and of a Henry marked model 1866 Winchester, show both their frames to be cast of “Gunmetal”.

The Confederate States of America manufactured weapons under some material constraints. Nevertheless, the one Confederate revolver I was able to examined indicated a sophisticated degree of metallurgical control. The lockframe analysis of this Spiller & Burr revolver fell exactly within our contemporary specification for Valve Bronze (a.k.a. Navy M, or Steam Bronze). That is, 88% Copper, 6% Tin, 4% Zinc, and 1.5% Lead. I am told that this Spiller & Burr had been stored in an old horse barn. Store neither your modern ammunition, nor your powder flasks, either in the barn, or near the kitty litter!

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The cracks in the frame, shown here, along with several others in the grip frame, bring up an important point about copper alloys. They are all subject to “season cracking” in the presence of ammonia or other nitrogen compounds. A 1942 metallurgy book14 states: It is well known that the atmosphere in the vicinity of stables and farm yards is a very dangerous one for stressed brass, and in olden times a car garaged in farm buildings often exhibited many season-cracked brass parts. It is not such common knowledge that the urine of rodents and of some other animals—for example, cats—quickly produces season-cracking, and that many tons of cold-drawn brass have been ruined annually owing to the unwelcome attention of mice and rats in old warehouses. . .”

In the copper-tin-zinc series of alloys tin adds to strength, and perhaps to castability. From the 1840’s through at least the 1860’s, American brass gun mountings often were cast of an alloy with 2 or 3% tin and 15—18% zinc. During my testing I found this to be true of an Aston model 1840 “horse pistol” dated 1847, and several Colt revolvers dating from about 1848 through 1862. The guard of one Model 1860 Army, made in 1862, was cast of 78% copper 18% zinc 3% tin, with just under 1% lead. Later tensile testing showed that zinc was approximately twice as useful as tin for increasing strength, and this class of tin-bearing alloy went out of use.

The U.S. attempt at a metal “gold” dollar used a sort of copper-zinc-manganese-nickel bronze. George Washington has his portrait on this one, of metal which is about 78% copper, 12% zinc with 5% each of manganese and nickel.

Brass Brass is normally thought of as copper with zinc added. Modern cartridge brass is 70% copper 30% zinc. Copper-zinc alloys range from 5 to 40% zinc. Early metallic cartridges were of what today is called “gilding metal”, an alloy of copper with just 5% zinc. The zinc improved both strength and ductility, so the metal better withstood drawing into a cartridge case.

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Below is a .45-70 “Multi-Ball” cartridge, designed to more effectively destroy the last free people in North America. The case is 94.8% copper 5.2% zinc, known at that time as Bloomfield’s Gilding Metal15. This 5% zinc alloy is stronger than pure copper, but not as strong as the 70% copper 30% zinc cartridge brass used today. Gilding metal is now used for bullet jackets (metal patched bullets, to use an older terminology)

A Batty “Peace Flask” dated 1848 has a body of similar composition. It is 94% copper 5.3% zinc, with residual amounts of lead, 0.4% and nickel, 0.3%. The spout is more or less conventional brass, 76% copper 23% zinc, with residual amounts of lead, nickel and iron. In both parts lead might have been added intentionally, nickel and iron just came along with the copper ore at that time. The brass patchbox lid & head, buttplate and trigger guard of this Harpers Ferry rifle dated 1818 all fall into the chemistry range of 64-76% copper, 20-34% zinc with 1.3-2.5% lead. Lead in these and other brass parts is the reason one must not heat brass to bend it. The lead melts, or comes close to melting, and with a little bending it runs along the grain boundaries so that the part breaks, or crumbles, in two. Bend all brass, new or old, at room temperature Pinchbeck alloy is a brass made with relatively low zinc content. Various references state anything from 7% to 19%. It resembles 20k gold in appearance, and was often used as a cheap substitute. It was invented by Christopher Pinchbeck, c1670 - 1732. Pinchbeck was a London maker of clocks, jewelry and musical automata. Whereas Pinchbeck himself clearly labeled his jewelry, later dishonest jewelers passed off pinchbeck alloy as genuine gold. In the 19th century pinchbeck" became a metaphor for spurious or counterfeit.

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The grips of miniature pocket pistols such as this one, about 1-3/4" long, were sometimes made of alloy generally called Pinchbeck. Pieces that date after about 1840 are rarely of true pinchbeck.

Pinchbeck became supplanted by 9K gold, legalized in 1854, and newer gilding techniques.

German Silver, Nickel Silver The most commonly available “German” silver alloy available today is called, variously, Nickel silver 65-18, or 18%—alloy A. The UNS number for this grade is C75200. Nominal chemistry is 65% copper, 18% nickel and 18% zinc. It has a silver-white color. The whiteness in nickel silver comes mostly from the nickel content, and to a lesser degree from zinc. I have observed that the alloy used on old American rifles has a more yellowish cast than seen with modern alloy.

White colored copper-nickel alloys had been used in Europe and China for centuries. Our metal called German Silver was developed by Berndorf AG in 1823, and tradenamed "Alpacca". There are many “nickel silver” alloys listed today. One current alloy which is actually tradenamed German silver, rather than Nickel silver, is 65% copper 12% nickel and 23% zinc. UNS C75700. Because of lower nickel, this grade may be expected to be somewhat less white in color than the 65-18 alloy. By comparison it appears yellowish. This matters when one attempts to repair an inlay on an old rifle, and exact color match becomes important.

The German silver trim on the sheath of this old Bowie knife, marked NON•XLL Joseph Allen & Sons, Sheffield is 61% copper 24% zinc 14% nickel, with assorted residuals. This metal has a yellowish cast, which is not matched by the new sheet of nickel silver in my shop.

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Pewter was an alloy of tin, lead, and copper, occasionally with antimony. Britannia metal, 93% tin 5% antimony and 2% copper is used today, instead of the old lead-bearing pewter alloys. To get the gray or dark gray appearance of an old cast pewter nose-cap on a percussion rifle, use one of the old alloys of tin, lead and copper, or for convenience just tin and lead. My uncle sent me this antique pewter mug from England after WWII. I used to drink milk out of it as a child. Some would frown on this practice now. The bottom is pitted from corrosion, and there are whitish corrosion products around the inside surface. Recent chemical analysis showed this old English pewter to be 95.7% tin, with 1.6% of lead, 1.7% antimony, 0.7% copper, and a little arsenic, 0.2%, for good measure. Made me what I am today.

This very old plate is closer to what I think of as pewter. It is 82.5% tin, 16.5% lead and 0.9% copper. Not a good idea to eat tomatoes off of such a plate.

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Tin Usually when one says "tin" one means tin plated iron, such as a modern tin can or antique lantern, candle mold, &c. This unpleasant relic of our 19th Century Indian policy was on display at a local show. It is a solid tin alloy. The tin is alloyed with a little antimony and copper for strength. Analysis is: 91-1/2% tin, 5-1/2% antimony, 1-1/2% lead, 1% copper and 1/2%silicon Whoever No 48 may have been, US policy was that his body belonged to the US Gov't and not to his surviving relatives or tribe. This is our history. "It is, to be sure, a hard thing to say, but there is safety in extermination alone, and this can be effected only during the early spring, when the Indians are in their villages." A Stage Ride to Colorado, Harper's New Monthly Magazine, No. CCVI - July, 1867 - Vol. XXXV

Silver available in jewelry supply stores is sterling silver, 92.5% silver 7.5% copper. Coin silver was typically 90% silver 10% copper. The copper addition made it a bit harder, to better survive circulation. Coin silver has a slightly different color than does pure silver. Old silver may have a few tenths of a % lead in it, a residual from the refining process formerly used. Silver plating on old firearms has a tin addition, in the range about 3 to 6%. When coin or sterling silver is annealed in air, the copper oxidizes faster than does the silver. After the black copper oxide scale has been removed by pickling the copper is depleted, and the surface enriched in silver. 4 Reales coin from the 1540’s, Mexico mint, Juan Gutierrez assayer. The fineness of the bullion was set at 93.051% silver16. Because the copper-depleted surface has not been worn away from this coin, the surface is enriched to 98.9% silver rather than the specified 93% silver. There was only 0.7% copper.

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Refining operations at that time involved lead, and there is a residual 0.3% lead in this coin. What I find interesting is that it also has 0.1% tungsten, from the original Mexican silver ore.

Nominal Chemical Analysis of Copper Alloys

Common UNS Copper Tin Zinc Lead Nickel Name number17

Nickel Silver C75200 65 -- 17 -- 18 German Silver C75700 65 -- 23 -- 12 Cartridge Brass C26000 70 -- 30 -- -- Free Cutting Brass C36000 62 - - 35 3 - - Bell Metal (cast tin bronze) C91300 80 19 -- -- (0.5P) Red Brass C23030 85 -- 15 -- -- Valve Bronze C92200 88 6 4 1 -- Gunmetal C90500 88 10 2 -- Leaded Com'l Bronze C31600 89 -- 8 2 1 Commercial Bronze, 90% C22000 90 - 10 -- Phosphor Bronze C52480 90 10 -- -- -- Gilding Metal C21000 95 -- 5 -- -- Ampco 45 C63000 82 - - - - - - 5 Ampco 45 also contains: 10% aluminum, and 3% iron UNS stands for Unified Numbering System designation, meant to render all old trade names and Copper Development Association numbers obsolete. Nevertheless, if you buy cartridge brass the supplier will call it C260, not C260, &c. UNS numbers are used in the U.S.A. only. Europeans use EN, European Normal, which standards appear to be largely adapted from the German Industry Standard (DIN).

Chemical Analyses: All copper, silver and lead alloy analyses in this paper were performed by an Innov-X Systems Model #XT-245S spectrometer. This X-ray fluoroscope leaves absolutely no mark on the metal.

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Nominal Carbon Content, Modern Carbon Steels

AISI Carbon Common Applications 1018 0.18 “Mild Steel” can be case-hardened 1035 0.35 Shafts, Gears 1060 0.60 Sledge hammers 1070 0.70 Springs 1095 0.95 Star drills, Cement Chisels, Springs

US and English measures multiply by to get ell 45 inch rod 16.5 f00t league 3 mile pound 7000 grain cwt (hundredweight) 112 pound Old French measures pouce 12 ligne pied 12 pouce pied 1.066 feet arpent 180 pied arpent 192.24 feet (US Standard) livre 0.9266 pound (US Standard)

Most of these are from: www.convert-me.com

Old Chemical Names Aqua Fortis nitric acid, HNO3

Black Brimstone crude sulphur

Black Lead, Plumbago graphite

Blue Vitriol, Blue copper sulphate CuSO4•5H2O Copperas

Butter of Antimony amtimony trichloride SbCl3

Brimstone Sulphur, S

Copperas originally blue vitriols, Later sometimes used for all vitriols/sulphates

blue copperas copper sulphate, CuSO4

green copperas ferrous sulphate FeSO4•7H2O

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Old Chemical Names, continued

Corrosive Sublimate mercuric chloride HgCl2

Crystallised Vertigris cupric acetate, Cu(C2H3O2)2•H2O

Cyprial Vitriol copper sulphate CuSO4

Dragon’s Blood the resinous fruit of Daemonoraps; also resin from the fruit of a Malayan rattan palm Calamus Draco, other species of Calamus, or the tropical American tree Lingoum Draco, or the blood tree Croton Draco

Minium red lead, Pb3O4 (formerly referred to cinnabar, mercuric sulphide, HgS)

Muriate of Iron iron chloride

Spirits of Wine ethyl alcohol C2H5OH

Sweet Spirits of Nitre 4% solution of ethyl nitrate, C2H5NO3 in alcohol

Shell lac orange shellac

Spirit of Hartshorn ammonia, NH3

Sugar of Lead lead acetate, Pb(CH3CO)2•3H2O (saccharum saturni)

Tincture of Steel, of Iron alcoholic solution of ferric chloride FeCl3•6H2O

Gum Sandarac resin from the Sandarac, or avar, tree, Morocco.

Vitriolic acid, sulphuric acid, H2SO4 Oil of Vitriol

Sources for chemical names include: Browning of Firearms (Part Two—Conclusion), C. Meade Patterson, The Gun Report, February 1962 The Condensed Chemical Dictionary, Fourth Edition, Reinhold Publishing Corp, 1950 NY

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References 1. Captain John G.W. Dillin, The Kentucky Rifle, 1924 2. Walter M. Cline, The Muzzle-Loading Rifle Then and Now, 1942 3. Merritt Roe Smith, Harpers Ferry Armory and the New Technology, ©1977 4. Engineering Properties of LA-LED®, La Salle Steel Co, July 1981 5. On Damascus Steel, Leo S. Figiel, M.D., ©1991 6. Harold R. Mouillesseaux, Ethan Allen, Gunmaker: His partners, Patents & Firearms, 1973 7. Joseph G. Rosa, Colonel Colt London, The history of Colt’s London firearms 1851-1857, 1976 8. Ned H. Roberts, The Muzzle-Lading Cap Lock Rifle, Fifth Printing 1958 9. S. James Gooding, The Canadian Gunsmiths 1608 to 1900, Museum Restoration Service, West Hill, Ontario 1962 10. Roy Marcot, Remington “America’s Oldest Gunmaker”, ©1998 11. Donald L. Ware, Remington Army and Navy Revolvers 1861 – 1888 ©2007 12. Sources for the History of the Science of steel 1532 – 1786, C.S. Smith, ed. ©1968 13. Hazlett, James C., Edwin Olmstead, and M. Hume Parks. Field Artillery Weapons of the Civil War. Newark: U. of Delaware Press, 1988.

14. J. Dudley Jevons, The Metallurgy of Deep Drawing and Pressing, ©1942 15. Albert Frasca, Robert Hill, The .45-70 Springfield, ©1980 16. Robert J. Nesmith, The Coinage of the First Mint of the Americas at Mexico City, 1536 – 1572, The American Numismatic Society, New York 1955.

17. Metals and Alloys in the unified Numbering System, 10th edition. SAE HS-1086/2004, ASTM DS-561

A late addition. One reason the original Damascus or wootz steel has been so difficult to recreate is the effect of trace amounts of elements such as vanadium and molybdenum, present in the original ore at Hyderabad. These effect a banding of the cementite (iron carbide) which give this steel a "watered" appearance. See: The Key Role of Impurities in Ancient Damascus Steel Blades, J.D. Verhoeven, A.H. Pendray and W.E. Dauksch, JOM, 50 (9) (1998) pp 58-64

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Batty 1848 Peace Flask

The “copper” body is actually gilding metal, with a chemistry of 94% copper 5.3% zinc, 0.4 lead, residual nickel

The spout is similar to modern brass: 76% copper 23% zinc 0.8% lead, residual nickel

©2013 James Kelly, Metallurgist jkellymetal@gmail.com