For several years I have had gunpowder manufactured of various sizes, at the sight of which most sportsmen would express their astonishment.
One objection held by sportsmen to the large grained gunpowder is that it does not come up the nipple of the gun; now although I do not consider this at all important, still if the specific gravity of the gunpowder were increased by compressing 11⁄2, 2, or 3 grains of gunpowder into the space of 1 grain, by means of hydraulic pressure, this objection would at once be obviated; whilst at the same time, the powder would be less liable to absorb moisture, or to become friable with age: either of which conditions is incompatible with good shooting.
The granulating of gunpowder, to be of the greatest benefit, should be on a uniform principle; the manipulation should be alike in all particulars, but especially in that part of the process which determines the specific gravity. The hydraulic pressure on the cake should be alike in all cases: in fact, the various sizes of grain might be produced from the same cake, and the desired object be thus obtained. But so long as the practice is followed of producing large grain from less condensed cake, the article produced will give unsatisfactory results; and the advantages which might be attained, as my experience denotes, and which would be of the greatest service, alike in sporting, rifle, and artillery powder, will be nullified.
Great improvements are yet to be made, especially in the powder used for artillery; whilst range, accuracy, and lessened recoils are points which may be determined with almost mathematical precision.
Great fame is in prospect for any one who can grasp and handle well this granulation principle; especially if he can define the sizes to be used for different varieties of guns. Artillerists who contend that a medium size grain, to suit all sizes of gun, is advantageous, might as well contend that cannon of a medium size would be preferable to so many different sizes, because, though we lose in range, accuracy, and recoil, it would be more convenient to have but one sized gun.
In making large grained gunpowder, the manufacturers defeat one of the main objects to be gained by granulation, from not subjecting it to the same amount of pressure which is necessary for the granulation of the very fine grain. In granulating very fine powder, it is necessary to subject the cake to such an amount of hydraulic pressure as shall give the mass a marble-like structure, or during the process of granulation, the whole of it crumbles into dust; but the coarser gunpowder may be granulated without subjecting it to this high degree of pressure, hence each grain is more porous and of lesser specific gravity: a difference which it is most important to avoid. It is clear, therefore, that according to the present mode of manufacturing gunpowder, the large and the fine grain are of very different kinds; the main difference being in their specific gravities. Gunpowder of less density burns with greater rapidity, because it is more open and porous; and if uniform density was observed, the diversity in the size of the grain need not be so great; whilst, at the same time, this anomaly might be avoided—that the same measure of fine and large-grained gunpowder contains a difference of the expansive element amounting to fifteen or twenty per cent. As gunpowder is now manufactured, it is highly necessary in all comparative trials to weigh, and not to measure the charge, or the results will be deceptive and worthless. The granulation question struggles with undeserved difficulty. Gunmakers, either not understanding the question, or constructing the chambers of their guns improperly, and not using suitable nipples, decry the adoption of large-grained gunpowder; but they forget the increased range obtained in the killing from their guns, and the éclât a long shot produces. In trials of guns at thirty or forty yards, the difference in the shooting with fine and large-grained gunpowder is not so apparent, and the maker exclaims, “Oh! the fine powder shoots stronger, and as close as the coarse.” I admit this to be the case, at short distances; but the great advantage of using the large grain is sufficiently evident when shooting at forty-five, fifty, and sixty yards, for then the fine grain entirely fails: simply from the oft-repeated fact, that the fine powder is more of a propulsive, while the large grain is an expellant force; so that according to the law of resistance in aëriform fluids, the one is sooner reduced to medium velocity than the other, which exerts its action more evenly. Powder of larger grain is thus more suitable for the larger sizes of shot, and would give an increased range in usual shooting, for the shot is kept better together, and is projected to greater distances. A common way of testing the quality of gunpowder is, to rub it between the hands, and observe the darkness of the stain; the darker the stain the more inferior the gunpowder is held to be. This test is, however, decidedly fallacious, because the gunpowder may be of low specific gravity, or it may have become friable from age and other causes.
Whales are shot with gunpowder proportioned to the weight of the harpoon required to kill them. Duck guns of the largest calibre are comparatively useless unless the gunpowder used is granulated according to the weight of the projectile; and the same law holds in regard to the most “mammoth” engine yet to be devised by the mind of man.
Gun-cotton has been before the world for some years, but, except as a curiosity, it has attracted little public attention; neither has it gained any reputation as a projectile force. It may be prepared by steeping cotton wool for a few minutes in a mixture of nitric and sulphuric acids, thoroughly washing, and then drying at a very gentle heat. It consists chemically of the essential elements of gunpowder: viz. carbon, nitrogen, and oxygen; but, in addition, it contains another highly elastic gas, hydrogen. The carbon in the fibres of the wool presents to the action of flame a most extended surface in a small space, and the result is an explosion approaching as nearly as possible to the instantaneous: in consequence of its rapid ignition it produces a violent kick; sufficient time is not given to put heavy bodies in motion, hence it cannot be usefully employed as a projectile agent. No one who values his limbs should trifle with it, for fearful accidents have resulted from its exposure to the heat of the sun, and other very simple causes.
There is an instrument used by some sportsmen, and strongly recommended by many gunmakers, for testing the strength of different kinds of gunpowder. It consists of a chamber closed by a spring, and fired like an ordinary pistol. When the powder explodes the spring is forced forward, and moves an index round a graduated circle; the more quickly the powder explodes the farther does it lift the spring; hence this is a measure of quickness of fire, but not of expellant force; and from the observations which have been made on gunpowder, it must be evident to any one who has paid the least attention to the subject, that this instrument is utterly useless.