657 



GUN. 



GUN. 



669 



necessary to bring the fire into a good state. The junction of the 

 several lengths of rod necessary to make a twisted barrel is often 

 effected by cutting each off in a sloping direction, and leaving them to 

 be joined in the general welding operation ; but it is better to weld 

 them together before the twisting is completed. After welding, the 

 barrels are re-heated to a welding heat, a few inches at a time, and 

 hammered in a groove to the required size. Sometimes they receive 

 a subsequent hammer-hardening in like way, when cold j but though 

 this improves them much, it is often neglected. 



After welding, the barrels are very carefully examined, and if needful, 

 straightened by a few blows of the hammer. Holland states that their 

 soundness is tried also, by placing one end in a bucket of water, and 

 sucking with the mouth at the other end, until the barrel is full of 

 water, when, if there be any crack or flaw extending through the 

 substance of the metal, it may be detected by the appearance of 

 moisture on the outside. They are then bored in a machine with an 

 angular plug of tempered steel [BoBiNO INSTRUMENTS], which is 

 caused to revolve rapidly within the barrel, a stream of cold water 

 being directed upon the outside to check the heat generated by the 

 excessive friction of the tool. Greener states that the barrels are not 

 annealed for this purpose, as Dr. Ure has represented in the ' Dic- 

 tionary of Arts." The outside of the barrel needs also to be made 

 smooth and even, which was formerly done by applying it to the 

 surface of a large grindstone, the workman allowing the barrel to roll 

 slowly through his hands, BO as to present every part of the surface 

 successively to the stone ; but this process is now in a great measure 

 superseded by turning in lathes, a method which claims great economy, 

 as well as superiority in point of accuracy, and the advantage of doing 

 away with a most unwholesome business, and one by no means un- 

 attended with danger. In a lathe it ia easy to ensure the perfect con- 

 centricity of the inner and outer surfaces of the barrel, and the perfect 

 rotundity of the exterior surface, whereas, under the old plan of 

 grinding, the sides of the gun were often very unequal in thickness, one 

 side being in some instances nearly twice as thick as the other. In all 

 cases it is advisable to forge the barrels as nearly as possible to then- 

 intended dimensions, in order that as little as possible of the surface, 

 which has been condensed by hammering, may have to be removed. 

 After the first or rough boring the interior is fine-bored with an instru- 

 ment having but one cutting angle, which is kept to ita work by strips 

 of soft wood attached beside it. Generally speaking, barrels are bored 

 with a perfectly equal cylindrical bore ; but some gun-makers prefer 

 enlarging the bore a little towards the breech, under the idea that the 

 consequent contraction of the muzzle will cause the shot to fly more 

 closely. The breech end of the barrel is then tapped with a screw-thread, 

 to receive the breech-plug, which closes it at that end, and forms the 

 abutment for the explosive force of the powder, and in which, in muny 

 cases, is formed the chamber to hold the powder, and the narrow 

 passage by which that chamber is connected with the touch-hole. The 

 best form of this chamber, and of the connection with the touch-hole, 

 is a matter upon which gun-makers differ widely. 



The barrels are then ready for proring, which consists in firing them 

 in a building in which their explosion can do no harm, with a charge 

 four or five times as great as they will have to bear when in use. A 

 great number of barrels are fired at once, by laying them upon a strong 

 framework of wood, with their touch-holes downwards, and connected 

 with a train of powder which is conducted outside the building, 

 within which is laid a heap of sand to receive the bullets. Common 

 barrels are allowed to lie twenty-four hours in the proof-house un- 

 touched, in order that, by the action of the nitre in the gunpowder, 

 any crack or flaw may be rendered visible. They are then carefully 

 examined, and such as show any defect, or have bulged with the 

 explosion, are returned to be reforged, after which they must be 

 I again, while such as have stood the test satisfactorily arc 

 stamped with a distinguishing mark. Notwithstanding the strict 

 regulations which require every barrel to be thus tested, Greener thinks 

 that in many cases the proof-mark is forged, and states that some- 

 times a cheat is committed by welding unproved tubes on to pistol 

 barrels which have been proved, so as to convert them into gun- 

 barrels, for the sake of saving the. difference of a few pence in the cost 

 of proving. 



Sporting guns are very often made with two barrels fixed side by 

 side upon one stock. Such barrels are made separately, and have their 

 adjacent side* filed flat in order that they may lie close together. 

 They are secured together by riln running between them from end to 

 rml, and filling up the spandril-shaped grooves formed by their contact. 

 For general sporting Greener says that they should not be mounted 

 with the bores perfectly parallel with each other, but slightly con- 

 verging, no that their line of fire may meet at a given distance ; but 

 opinions differ as to the best inclination or degree of convergence. 



The wiKPt|i:ii i-irkt upon which the barrel m- barrels are mounted is 

 most commonly in:ide of walnut-tree, though bird's-eye maple and a 

 few other woods are occasionally used. This is fitted to the barrel so 

 accurately as to leave as little as possible to depend upon the metal 

 fastenings by which they are connected together. Great care should be 

 taken to adapt the weight, length, and curvature of the stock to the 

 person for whose use it is intended. Greener observes that it is very 

 common to make the stocks of sporting guns too short and too crooked ; 

 and Colonel Hawker, in a passage quoted by Holland, ays that " the 



length, bend, and casting of a stock must, of course, be" fitted to the 

 shooter, who should have his measure for them as carefully entered in 

 his gunmaker's books as that for a suit of clothes on those of his 

 tailor." " He has then," the colonel adds, " only to direct that his 

 guns may be well balanced, to do which the maker will introduce lead 

 in proportion to their weight ; eo that, on holding each of them flat on 

 the left hand, with the eud of the feather-spring about half an inch 

 from the little finger, he will find a sufficient equilibrium to make the 

 gun rest perfectly steady on the hand." When the shaping of the 

 stock is completed, it is shod with steel for fowling-pieces and rifles 

 and brass for muskets, the trigger-guard and other metallic fittings and 

 ornaments are let into the wood, and every part is fitted with suitable 

 screws and fastenings, after which the whole is taken to pieces ; the 

 woodwork is finished by staining and polishing, the metalwork is filed 

 and blued, and the barrels are sent to be finished, which is done in 

 various ways. 



When intended to be bright externally, barrels are. filed all over with 

 smooth files, and then polished with a steel burnisher. Military 

 muskets were formerly polished in this way, but the time and labour 

 required to maintain the polish proved so harassing during service, 

 that the Duke of Wellington, during the Peninsular war, dispensed 

 with it, and allowed the muskets to be browned. Of the various 

 methods of browning or staining barrels, of which every gun-maker has 

 his own, we may notice two, in the first of which; described by Holland, 

 the solution employed consists of half an ounce each of nitric acid and 

 sweet spirits of nitre, one ounce of spirits of wine, two ounces of blue 

 vitriol, and one ounce of tincture of steel. These ingredients are 

 mixed, the vitriol being previously dissolved in sufficient water to 

 make, with other fluids, a quart of mixture. The barrel, being first 

 thoroughly cleaned from grease and dirt, aud having the muzzle and 

 vent stopped up with wood, is wetted all over with this mixture, 

 applied with a sponge or rag, and then exposed to the air for twenty- 

 four hours, after which it is rubbed with a hard brush to remove the 

 oxide formed on the surface. These operations may, if requisite, be 

 repeated two or three times, until the barrel becomes perfectly brown. 

 It is then carefully brushed, wiped and immersed in boiling water 

 which holds a quantity of alkaline matter in solution, in order that 

 the further action of the acid mixture may be prevented. The barrel 

 is then dried, rubbed smooth with a burnisher of hard wood, and 

 heated to about the temperature of boiling water, after which it is 

 coated with a varnish composed of spirits of wine, one quart ; pulve- 

 rised dragon's blood, three drachms ; and bruised shell-lac, one ounce. 

 When this is dry the barrel is finally rubbed with the burnisher to 

 give it a smooth glossy face. The second method we shall allude to is 

 called imuke In-own or stain, and is recommended by Greener as one of 

 the best preventives of fraud in the manufacture of twist barrels, 

 since it brings out the grain or pattern in a way which, to say the 

 least, it is not easy to imitate. For producing it, the barrels are 

 anointed with a little vitriolic acid, which is washed off, and the 

 surface rubbed dry. A forge fire is then lighted and blown up, with 

 coals containing as much hydrogen gas and as little sulphur as pos- 

 sible. When the coals are burnt until they give out a clear white 

 flame, without any black smoke, the barrels are passed gradually back- 

 wards and forwards through the flame until they are covered with a 

 black Booty covering. They are then placed for eighteen hours in 

 a damp cool cellar, by which the iron particles will become coated 

 with a red rust, while the steel retains its original sooty coat. The 

 rust and soot being brushed off with a brush of steel wire, the barrels 

 are washed and polished with a linen cloth dipped in water and fine 

 washed emery, by which the two metals become very distinct, the 

 iron being dark and the steel bright and polished. After drying, the 

 smoking is repeated, and the barrels are left in the cellar for twelve 

 hours, and treated as before ; and thus the process is repeated until 

 the barrel becomes as dark as may be wished, the darkest colour 

 attainable being a fine purple-black on the iron, with a copper tinge on 

 the steel. 



The progressive steps in the invention of the fire-look, or that con- 

 trivance attached to the breech of a gun by which the powder in the 

 touch-hole is ignited, are noticed under ARMS. The essential qualities 

 of a gun-lock are, first, that it should work easily and efficiently, so 

 that the force required to move the trigger and release the spring by 

 which the hammer, or striking part of the lock, is moved, shall not be 

 sufficient to interfere with accuracy of aim and rapidity of firing ; 

 secondly, that it should not be liable to go off at half-cock (a position 

 in which the lock should always be kept until actually preparing to 

 fire, and in which even the application of force to the trigger has no 

 effect upon it), or in any other way accidentally ; and thirdly., that 

 when the piece is on full cock, the pulling of the trigger should cause 

 the gun to fire with certainty. The delicate workmanship of modern 

 locks, the manufacture of which forms a distinct trade, which is carried 

 on chiefly at and in the neighbourhood of Wolverhampton, leaves 

 nothing to be desired in efficiency and ease of working, while the 

 ingenuity which has been devoted to this branch of mechanical science 

 has provided numerous admirable plans for lessening the risk of acci- 

 dent by means of tumblers or other contrivances for securing those 

 parts of the lock which might occasion danger by their accidental 

 removal. Some such contrivances, to give a fair account of which 

 would require too much space in this article, are illustrated by 



