As soon as the barrels are properly jointed; care must be taken to see that they are perfectly level. If the barrels are not level, it will be impossible to shoot correctly, as one barrel will throw the shot above, the other below the mark. This being done, the barrels are bound together and brazed with hard solder or brass, for about four or five inches. Greater injury cannot be done to barrels than by this pernicious practice; for they cannot be brazed without being heated to a white heat; and by this heat all the advantages derived from hammering are dissipated at once: the condensation is gone, and the strength is reduced at least 12-1/2 per cent. And for what purpose? Under the pretence that the barrels are firmer and not so liable to become loose. This is a point trivial in importance compared to the excellence and strength of the barrel; for even if they have received no more hammering than is necessary in the forging, they are still injured to the extent of 12-1/2 per cent.: for even beating them when hot improves them much, provided they be not heated again; but if they have been cold hammered, the injury is full 30 per cent. This circumstance shows how little the principles of gun-making are understood by the first gun-makers, the brazing of barrels being practised by all.
Mr. Wilkinson admits this, for he says--“The practice of brazing the barrels is decidedly injurious, by softening that part more than the other; but if they were only soft soldered, the inconvenience would be far greater, as the barrels would be liable to some accident by the repeated expansion and contraction that takes place in firing, as well as by the force required to turn out the breechings.” I can only say that I have had considerably more than five thousand pairs of barrels made and put together with soft solder only, and not one pair has come asunder from any of the causes mentioned; nor ever will, with fair play. On the contrary, barrels brazed can never be sound; for at some distance from the part heated for brazing, you cannot get the barrels re-tinned effectually, and thus for a considerable space between the soft and hard solder, there is no cohesion at all. Barrels brazed together only for three or four inches at the breech-end, can never be sound: they almost invariably become so rusted under the rib, in a few years, as both to seriously injure the barrels, and force the rib upwards; therefore, if you hard solder at all, do so from breech to muzzle, as that will be preferable to partially doing it. I feel quite satisfied, and can prove it to demonstration, that this is undoubtedly the most injurious process to which iron can be subjected; and I believe the prejudice with which the London barrel-makers stick to this practice is productive of considerable injury to them: more especially when we recollect that they are the advocates (in practice) of a very inferior quality of Damascus barrels: an iron very susceptible of injury. The Belgian barrels, and French also, are of good iron; and I fear not contradiction in asserting their inferiority to English barrels mostly consists in the foolish practice of brazing them together from end to end. Both chemically and mechanically it is a practice for which no valid excuse can be offered.