The first projectiles to be discharged from any type of firearm were stones, feathered iron arrows, and iron shot. These were discharged from cannons.18 The first handheld firearms had bore diameters between 1.5" and 2.0" and suitable small round stones were used as projectiles. The earliest use of lead in bullets would appear to have been about 1340 and these consisted of spherical lead bullets.19 Firearms of this era were large and heavy and from this time to the present day there has been a gradual reduction in bore size and weight. By the time the flintlock pistol came into use, the spherical lead bullets were between 0.6" and 0.7" in diameter.* Bullets of this type were used for many years in smooth bore muzzle-loading firearms where the bullet did not have to be a tight fit in the bore.
Rifling of the bore was found to improve the accuracy and consequently the effective range of firearms, and was first applied to firearms by German gunsmith Augustin Kutler in 1520.20 The introduction of rifling coupled with the development of breech loading firearms focused attention on bullet design.
With rifled bore firearms the bullet had to be a tight fit; otherwise it would not grip the rifling when discharged but, if it was too tight a fit, it was difficult to load the gun. The problem of bullet size created particular loading problems for rifled muzzle-loaded firearms and for rifled breech-loading firearms. A tight-fitting spherical lead bullet was difficult to load, especially when the bore or chamber was dirty with fouling from previous shots.
The first attempts to solve the problem involved the use of a belt (driving band) around the lead ball. The bullets were cast in a mold and the lead belt was an integral part of the bullet. The spherical part was an easy fit in the bore and the belt was made large enough to fit the rifling. This bullet proved to be unsatisfactory as the belt caused the bullet to tilt after leaving the muzzle and it was very susceptible to the effects of the wind, causing poor accuracy.
During this period a large number of bullet designs were produced and tested, and it was found that an elongated bullet was much more efficient than a spherical one. The elongated bullet had greater weight for a given diameter and was more stable in flight. In 1855, General J. Jacob produced a cylindro-ogival bullet with four cast-on lugs to engage the rifling. Another
* The well-known term "biting the bullet" means exactly what it says and originates from surgery performed on or near the battlefield before the advent of anesthetics, the injured party bracing himself by biting on a bullet.
mechanically fitting bullet was produced by English engineer Joseph Whit-worth who developed a hexagonal bored barrel and hexagon-shaped bullets. The hexagonal bullet had six flat portions along its cylindrical body which were given a twist corresponding to that of the rifling. Such mechanically fitting bullets were very difficult to manufacture and were soon found to be unnecessary. By this time the bullet diameter had been reduced to .45".
The first practical solution to the problem was developed in 1849 by Captain Minie of the French Army. He produced a cylindro-ogival bullet with a tapered hollow base containing a semispherical iron cup. When the gunpowder burned, the hot expanding gases forced the iron cup into the bullet, which spread the bullet slightly so that its sides gripped the rifling. It was soon discovered that the same effect could be obtained without the iron cup and the Minie bullet was abandoned.
In 1863, William Ellis Metford produced a cylindro-conoidal bullet with a shallow depression in its base. The bullet was made of lead hardened with antimony and the cylindrical part was wrapped in a sheath of paper. The shape and design of this bullet resembles the modern bullet.21
Another problem related to bullet design was the fact that the rifling could cause lead to be stripped from the bullet, resulting in "leading" of the bore, which has a detrimental effect on accuracy by deforming the bullet and reducing the efficiency of the rifling. The use of antimony or tin to harden bullet lead dates from the early nineteenth century. The use of hardened rather than soft lead serves to reduce leading of the bore and deformation of the bullet and also slightly reduces the extent of bullet deformation on hitting a target.
The use of hardened lead did not eliminate leading but it slightly reduced the extent of the problem. Lubrication of the bullet was found to significantly reduce the amount of leading by preventing the partial melting of the lead by heat due to friction. Lubricants such as tallow and beeswax were placed in annular grooves at the rear of elongated bullets.
The problems of leading and bullet deformation were eventually eliminated by the use of a bullet jacket (envelope). Such a bullet was introduced in 1883 by Major Rubin of the Swiss Army and consisted of a soft lead core covered with a copper jacket. This was an important step in bullet development because up to this time the rate of the rifling twist was limited by its effect on the unjacketed lead bullet. With this new bullet the rate of twist could be substantially increased and the rifling grooves could be made shallower. (The rate of rifling twist can be altered to give different rates of spin of the discharged bullet.)
A bullet jacket is normally harder than the bullet core material but soft enough to take up the rifling and not cause excessive wear to the barrel. Bullet jackets were for a long period made of cupronickel (80% copper, 20% nickel), gilding metal (90% to 95% copper, 10% to 5% zinc) or steel which was coated with a softer metal to prevent barrel wear and rusting.22 In 1922, 1% to 2% of tin was added to the gilding metal because of its lubricating properties.
Unjacketed lead bullets are unsuitable for use in most modern self-loading firearms. With higher-velocity firearms, melting and fusing of the exposed lead surface can occur causing leading of the barrel, deformation of the bullet, and a loss of accuracy of the firearm. Modern lubricated unjack-eted lead bullets are usually confined to use in lower-velocity revolvers and 0.22" caliber rimfire rifles and pistols, that is, firearms with a muzzle velocity of less than about 1,200 feet per second. Another important factor influencing the use of unjacketed lead bullets is that they are more prone to "feeding" problems in self-loading firearms because the exposed part of the unjacketed lead bullet is more susceptible to damage than its jacketed equivalent.
The vast majority of modern bullet types is either completely or partially jacketed, usually with gilding metal, and is produced in a range of shapes, sizes, weights, and designs depending on their intended use.
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