BAD leak PUNCTUM TKWZK Chapter Three is inseparably associated with them. The composition of black powder varies only slightly in different countries, the proportions being about 75°fo potassium nitrate (saltpeter), 10% sulphur, and 15% charcoal. The nitrate and sulphur must be of exceptional purity and only a few woods are suitable for making the charcoal. As a boy, the writer used to make his own black powder of about a 60-20-20 mixture. The saltpeter used was the ordinary commercial product and undoubtedly contained chlorate, perchlorate or even chloride. The sulphur was ordinary drug store, powdered sulphur, which usually contains some sulphuric acid, and the charcoal, by the grace of God, was made from willow ^ because it was found that willow charcoal would pulverize better than some others. The charcoal was correct but it will be seen that about everything eise v/as wrong, including the method of manufacture, which need not be gone into here. At the time, the product seemed to be a great success; it gave a loud report and produced much smoke but the manufacture of good black powder is no job for a child and requires much special equipment and above all, experience and skill. In some forms, its manufacture is bafHing even to experts.
The process by which black powder is made may be described briefly as follows: The ingredients, of proper purity, arc mixed together thoroughly and sifted. They are then "milled" or ground together in spccial stone or iron mills, with precautions to prevent friction or sparks, which makes a very fine and homogeneous mixture of the powder. It is next pressed into hard cakes or blocks which are dried and broken up to form the granules. These are graded for size by passing them through screens, which permit the largest permissable grains to pass through. The powder is caught on other screens that only permit the dust and grains that are too small to pass through. These grains arc glazed by rotating the powder with graphite in closed cylindrical drums, after which the powder is again sifted to remove graphite and dust. The milling operation takes hours and this, as well as practically all odier operations, are attended by danger of explosion unless special safety precautions are constantly observed. In fact, black powder is one of the most, if not the most dangerous of explosives to make, handle and store, because of the ease with which it can be ignited; a static spark may set it off and in loading it by machine there is a danger to a degree that docs not exist when loading smokeless powders. On the other hand, black powder is the safest tor handloacing purposes. The proper method of loading it in any cartridge is to use a charge that will fill the case to a point where it will be compressed slighdy, or packed by the base of the bullet when the latter 67 is seated to the proper depth. An over charge is practically impossible if the proper size granulation is used.
Black powder, as supplied for reloading purposes, comes in three different granulations. FFFg is the finest and is used only in cartridges of small capacity. FFg is the medium size of granulation and has the widest application of the three. It is used in all medium size cartridges. Fg is the coarsest granulation and is suitable only for use in large caliber rifle cartridges.
It is said that when black powder is fired it gives off about 44% of gaseous and 5Gfo of solid products; herein lies its great fault and lack of efficiency as compared with smokeless powders. The expanding gasses are the only part that causes movement of the bullet and the only way the velocity of a bullet may be increased with black powder is to increase the amount of powder that is burned behind the bullet, so as to produce more gas. The effort to obtain increased range and power in black powder cartridges can be seen from a study of the cartridges in common use about fifty years ago. The cases were continually being made with larger powder capacities to accomplish this result, but black powder, for sporting purposes, has largely gone into the discard in favor of the more efficient smokeless. The writer can remember when powder mills were fairly common establishments around the country and what ramshackle edifices they were. The practice was to build a stout skeleton framework of beams with a good strong roof with a flock of decrepit boards tacked on the sides. I believe the rule was not to use more than one nail to a board and for a very good reason. The workmen mixed the batches or prepared them for other operations and left the building. The machinery was started from outside, by remote control and was allowed to run for the proper length of time, after which it was shut off and the workmen returned. When, as occasionally happened, a "blow" occurred, the explosion followed the path of the least resistance and blew the build-68 ing as clean of boards as a plucked chicken is cleaned of feathers. It was rare indeed for anyone to get hurt and all the boys had to do was gather up the boards, tack them in place, clean up the machinery and business went on as usual.
But to get back to the powder itself. Black powder gives a rather heavy recoil as compared with smokeless. This is due to the large amount of solids produced whin the powder is burned; about 56% of the weight of the charge, which, from the standpoint of recoil, is just like adding that much weight to the bullet.
Recoil is divided into two parts; the primary rccoil which is due to the velocity and weight of everything that goes out of the muzzle of the gun as opposed to the weight of the gun itself. The products of combustion and the bullet that leave the barrel are known as the ejecta and include the weight of not only the bullet and solids of combustion but the weight of the gasses as well. If the ejecta were equal in weight to the weight of the gun, the gun and the ejecta would leave each other at equal velocities when the gun was fired but, of course, guns are much the heavier of the two and consequendy recoil at a very much lower velocity. The secondary recoil is due to the expansion of the gasses against the atmosphere, it also pushes the gun to the rear.
When smokeless powders arc fired, they also decompose into gasses and solids, but the solids represent only a small percentage of the total and they develop a much larger volume of gas than an equal quantity of black powder. This means that they can give bullets a higher velocity than is possible with black powder and that they are relatively free from fouling and smoke. This means that the weight of the ejecta is less, which makes for a reduction in rccoil, but the velocity of the ejecta is increased which partially offsets this.
Smokeless powders are more difficult to ignite than black powder and when first introduced, the black powder primers then in use would not ignite it properly. It was common practice to place a small priming charge of black powder in the base of a cartridge before loading the smokeless 69 powder charge, in order to get good ignition. The primer would ignite the black powder which, in turn, would produce an adequate amount of flame and heat to ignite the smokeless. This practice should not be followed in loading ammunition today, unless the circumstances are exceptional. With full charges of smokeless powders and modern primers, the addition of a black powder priming charge will increase the rate of burning of the charge over the expected point and can easily cause dangerous pressures. These priming charges may be used with reduced or low pressure loads but will rarely contribute anything to the performance of the ammunition.
Series of spark photographs made by the late Capt. Philip Quayle for Col. K. M. Cuits and published with the permission of the Utter. These show how gas escapes between the expanded neck of the cartridge case and the bullet, before the latter starts forward. If the necks did not let go of those bullets first, hew did that gas get out ahead or them?
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