The gunsmith's manual

Long and Short Barrels.—A long barrel may be preferable for several reasons: 1st. A longer distance between the sights is given and the back sight can be put farther from the eye, so that finer sighting is possible; 2d. A long barrel is steadier in off-hand shooting; 3d. It permits a slower burning powder to be used, so that the charge starts more slowly and yet allows the full strength of the powder to be used before it leaves the barrel, getting a high initial velocity with but little recoil.

The short barrel has an advantage over the long one inasmuch as it can be handled with greater quickness and the sight can be brought to bear more readily, especially if the game be moving. If the barrel be long enough to give the charge the full benefit of the propelling power of the powder it may be deemed all sufficient. Yet, as to this, tastes and experience may so differ as to raise many conflicting opinions.

Except in some localities, as in case of districts where the old-fashioned Kentucky rifle is used, long barrels have been pretty much abandoned. A few years ago it was not uncommon to find barrels three and even four feet long, now the lengths will range from twenty-six to thirty-two inches. The length of the old Government musket barrel was originally forty inches, but has been lessened about seven inches. With the long barrels, a coarse, slower burning powder may be used and get a good result, but as a general thing cut off the barrel to a convenient length for off-hand shooting and moving game, use a finer-grained powder, which will be quicker burning and just as good results are obtained.

A gun having barrels over thirty inches in length, must needs be made with heavy barrels, and is very fatiguing to carry in an all day hunt. A gun of this kind, to be safe and well-proportioned, ought to weigh nine or ten pounds.

If fine and quick-burning powder be used in a long barrel, the powder is flashed into propelling gas, instantaneously, and beyond a certain length of barrel has no further expansive power, and the result is a friction of the charge in escaping, that affects the shot and consequently the pattern on the target. If slow burning powder be employed in a short barrel, the whole of the powder cannot be so instantly flashed into the propelling gas and some portion of it is, as a result, driven unconsumed from the muzzle of the gun.

This fact can be very readily ascertained by firing a gun over a bed of clean snow or over a spread of white cloth. The unconsumed grains can be readily seen on the white ground. If a less charge be used in order to consume all the powder, less velocity will be given to the projected charge, and weak shooting and a poor, scattering effect on the target is the consequence.

Proof of Barrels.—In consequence of the bursting of guns of an inferior quality, all barrels of English manufacture that are intended for home use, and also those designed for exportation, except a certain class of arms, are required by law to be proved and stamped with the proof-mark and also what is termed a view mark, which is a stamp or impress of the inspection after the barrels were grooved. There are two of these proofs called, respectively, the London and the Birmingham proof. In 1855, an Act was passed by the English Parliament, called, “The Gun Barrel Proof Act,” which enacted that all barrels should be proved, first, in the rough, and was called the provisional proof, and afterward when the barrels were put together, breeched and percussioned they were proved again, and this was called the definitive proof.

The arms to be proved are to be divided into classes, and the first class comprises single-barrelled military arms of smooth bore, and they are not qualified for proof until they are fitted and complete to be set up or assembled. The second class comprises double-barrelled military arms of smooth bore and rifled arms of every description, whether of one or more barrels, and constructed of plain or twisted iron. The fourth class comprises double-barrelled guns for firing small shot, and these are subject to the two proofs, provisional and definitive. For provisional proof, if of plain metal, the barrels are to be bored and ground to size, the vent hole drilled of a size not exceeding one-sixteenth of an inch diameter, and a vent enlarged to one-tenth disqualified it for proof. Notches in the plugs, instead of drilled vents, also disqualified them. If the arms are of twisted metal, they are to be fine bored and struck up, with proving plugs attached, and vents drilled the same as in plain barrels.

For definitive proof the barrels, either plain or twisted, must be finished ready for assembling, with break-offs and locks fitted. The top and bottom ribs have to be rough struck up, pipes, loops and stoppers on, and the proper breeches in. The same finished condition is required for rifles, but, in addition, the barrels must be rifled. The third class comprises single-barrelled shot guns, and for proving they are to be finished ready for assembling, with breeches in; and all barrels, with lumps for percussioning, are to be proved through the nipple hole. The fifth class comprises revolving and breech-loading arms of every description and system, and for revolving arms are to have the cylinders with the revolving action attached and complete. The barrels for breech-loaders are subject to provisional proof, according to the class to which they belong, and to definitive proof, when the breech-loading action is attached and complete.

Barrels made by the United States Government, or barrels made for the Government, are subject to severe proofs. At the armory at Springfield, the barrels submitted for proof are loaded, first, with a 500-grain slug and 280 grains of powder, and afterward with a slug of the same weight and 250 grains of powder. An inspection of the barrel is made after each firing, and other inspections after rifling, browning, etc.

Probably the most severe proof of barrels was made with the Turkish Peabody-Martini rifles as made for the Turkish Government by the Providence Tool Co. The barrels were first proved for strength, and were loaded with 205 grains of powder and 715 grains of lead. The regular cartridge for service contains only 85 grains of powder and 480 grains of lead.

Proof Marks on Gun Barrels.—The marks applicable to the definitive proof are the proof and view marks of the two English companies, viz.: the London and the Birmingham. The provisional proof marks consist of, for the London company, the letters G. P., interlaced in a cypher surmounted by a lion rampant, and for the Birmingham company the letters B. P., interlaced in a cypher surmounted by a crown. The London marks are shown in Fig. 26, and the Birmingham in Fig. 27.

The method of affixing the proof marks in arms of the first and third classes, the definitive proof mark and view mark is impressed at the breech end of the barrel, and, if the barrel be designed for a patent breech, the view mark is also impressed upon the breech. In arms of the second, fourth and fifth classes, the proof mark is impressed at the breech end of the barrel; the definitive proof and view marks are impressed upon the barrel above the provisional proof marks. If the barrel be made with patent breech or with revolving cylinders or chambers, the view mark is impressed upon the breech or upon the cylinders or chambers, as the case may be.

On all barrels the gauge size of the barrel is struck both at the provisional and at the definitive proof. These gauge marks are readily recognized, as shown in the cuts of the proof marks.

Barrels stamped with London marks are not always made in London, for some gunmakers send their barrels to London to be proved, because guns so marked find a readier sale. Barrels with foreign proof marks are exempted, except in case of being marked as of English manufacture. Old muzzle-loaders, if of English manufacture, intended for conversion into other styles of guns, must be subjected to both provisional and definitive proof.

It is said to be a fact that the proof marks of both companies are forged and imitated, both in England and in Germany, and many cheap guns so stamped are exported to this country. A cheap gun, with the stamps mentioned, may be looked upon with suspicion as to its really having been in the official proof-houses.

The proof marks employed by the inspectors in the U. S. Government armories, and placed on all arms inspected by them, even if made in private armories, are V for viewed, and P for proved, together with the initial letters of the inspector’s name, and are found stamped on each barrel. On many guns of the old model arms will be found, in addition to these marks, the head of an eagle. This is the mark that indicated that the barrels were made at the armory at Harper’s Ferry, when those works were in operation.

Gauge of Gun Barrels.—Guns are gauged by numbers, and these numbers were originally designed to express the number of round balls to the pound that would fit the bore of the barrel. Thus a ten gauge, a ball of which ten made a pound, would fit the bore, etc. Ten and twelve bores are generally used by sportsmen, especially those who use breech-loaders. The twelve, perhaps, is the one most employed.

The following list shows the sizes of various gauges, the values of the numbers being those adopted by the English proof companies. The diameters of bores being expressed in decimal thousands of an inch:

Muzzle-loaders are of almost every variety of gauge, while breech-loaders are made of a limited number of sizes. The sizes of this class of guns are 8, 10, 12, 14, 16 and 20, and are limited to these sizes, there being no intermediate sizes. The 10 and 12 bore are mostly in use, the 12 being in especial demand. The calibre or bore of military guns during the Revolution was 75 hundredths of an inch, and has been reduced by successive stages until now it is but 45 hundredths. Down to 1856 the calibre of the Springfield musket was 58 hundredths. In 1856 it was changed to 50 hundredths or one-half inch; and again, in 1873, it was changed to the present calibre of 45 hundredths.

Bursting of Barrels.—Bursting of barrels may result from three causes: Poor quality of iron of which the gun is made; an excess of charge; or some obstruction in the barrel so as to form an air space between the charge and the obstruction. Of poor quality barrels, and excess of charge it is needless to make mention. The instances of bursting from obstructions forming the air space or chamber may be mentioned in military guns, firing the charge but neglecting to remove the wooden tompion from the muzzle of the gun. In sporting guns snow may accidentally get into the muzzle or a lump of dirt may “somehow” get in so as to fill the bore, and when the gun is fired, it will probably, yes, most certainly be blown off or blown open where the obstruction exists; the muzzle of a gun being thrust into water for a couple of inches or more will have like effect. The gas formed by burning the powder finds no outlet of escape, and the whole expansive force concentrates itself on the weakest portion of the barrel, and as a result it is forced apart. In good guns the portion toward the muzzle is the thinnest, and obstructions are generally at or above this place, and it is in this proximity where most guns are burst. If within three, four or five inches from the muzzle, the portion so destroyed can be sawed off, the barrels squared up and it will not always seriously affect the shooting of the gun.

In loading a gun be careful that there be no air space left between the charge and the ball or shot cartridge. In double guns, frequent firing the right barrel, which is the one fired the most, the recoil will often cause the ball or shot charge in the left barrel to be thrown forward from the powder, and when it is fired may either strain or burst the barrel. Even if there be a small air space between the powder and the ball or shot cartridge it will affect the shooting. Every one using double guns should accustom himself to the use alternately of both barrels, not only for safety but for good shooting. A barrel is often said to be a poor shooter, when its bad qualities may be wholly ascribed to the air space produced above the powder by the recoil occasioned by firing the other barrel.

To Prevent Gun Barrels from Rusting.—Heat the barrel to about the temperature of boiling water, no higher, and then cover it with a good coating of copal varnish. Let it stand at same temperature about half an hour, then rub off the varnish while still hot with a soft cloth. In this process the varnish will enter the pores of the metal sufficiently to prevent rusting, but will not show on the surface after having been carefully rubbed off as directed. A polished surface like that of a finished gun barrel, is not much liable to rust, and, indeed, seldom begins to rust, the rust starting in the pores of the metal and finally working outward. This being the case it will readily be seen that sheltering the pores by filling them with some kind of substance impervious to moisture cannot do otherwise than act as a splendid preventive.

Protection from Rust.—It sometimes happens that finished up articles in steel or iron must be laid away for a considerable length of time, in which case it is desirable to employ some means for protecting them from the effects of rust. One of the most common things is to either grease them or wrap them in a greasy rag. This may answer in many cases, but it is not nearly so good as to paint them over with a mixture of white lead and tallow in equal parts, the white lead to be such as has been ground in oil for the painter’s use. In this simple mixture will be found an effectual protection; and as the tallow will prevent drying, it may be entirely removed at pleasure by rubbing with a little kerosene or turpentine.

Where it is desirable to protect an article that must be handled a great deal, as gun-barrels on sale in a store, for instance, a very good plan is to heat the article sufficiently hot to readily melt beeswax brought in contact with it, then rub it thoroughly with the wax. Let it stand until the wax is about ready to harden, then rub off with a coarse woolen cloth. The wax remaining on the metal will not show, but there will be enough left to protect it from rust.