Ammunition in law includes a host of items. For the purposes of forensic ballistics, however, ammunition in common language means cartridges, propellants, primers and projectiles commonly used in small firearms. In crimes small arms are involved almost exclusively. The discussion, therefore, is limited to the ammunition of small arms only.
• According to Indian Arms Act, 1959, Ammunition means: “Ammunition for any firearm” and includes
(1) Rockets, bombs, grenades, shells and other like missiles.
(2) Articles designed for torpedo service and sub-marine mining.
(3) Other articles containing or designed or adapted to contain explosive, fulminating or fissionable material or noxious liquid, gas or other such thing whether capable of use with firearms or not
(4) Charges for firearms and accessories for such charges.
(5) Fuses and friction tubes.
(6) Parts of and machinery for manufacturing ammunition.
(7) Such ingredients of ammunition as the Central Government may by notification in the official gazette specify in this behalf.
A firearm cartridge has the following components:
1. Cartridge case or shell;
2. Primer;
3. Powder;
4. Wads;
5. Projectile(s); and
6. Lubricants.
1 Projectiles
Projectiles are pellets, buck shots, balls, bullets, etc., intended to cause injuries. They are hurled out by the gases produced by the propellants on discharge of a firearm. They vary in constructional materials, shapes and sizes and in their ballistics.
The projectiles used in firearms have undergone the usual evolution. The first projectile for the firearm was probably a stone of convenient size. The next logical development probably was an imitation of an arrowhead. But ultimately these initial projectiles gave way to spherical projectiles, which held the field for a long time and still continue to be used in smooth bore firearms. Further developments revealed that a spherical shape was not efficient ballistically. It gave way to conical bullets. Arrow like projectiles are also being reintroduced.
Lead, almost everywhere used for the projectiles was found indispensable, though for high velocity projectiles it was covered with a harder metal jacket. It has a high specific gravity. It has a low melting point. It can be molded into various shapes easily. It is comparatively cheap. However, the pure state, it is quite soft and gets deformed easily. The metal is, therefore, alloyed with other suitable metals, particularly with antimony. These alloys are quite hard and are being used where the projectiles have low and medium velocities.
The following compositions are common
- Lead (Pb) 90 – 98%
Tin (Sn) 2-10%
- Lead (Pb) 90 %
Tin ( Sn) 5%
- Lead (Pb) 85 %
Antimony (Sb) 15%
Other alloys of lead and mercury, lead and antimony have also been used. The percentages of the metals alloyed with lead have always been small.
Lead, as core material, has been placed in some of the modem rifles though not completely. For example, in Russian rifles (AK 47 and AK 743 the main pan of the core is made of steel but a small amount of lead is also part of the core, Other rifles structured on the Russian pattern have also similar core composition. Flechettes, arrow-like projectiles, and the pellets are also being made of steel rather than that of lead. Some pellets have also been made from bismuth and other materials. However, these non-lead projectiles are not common in India.
1.1 Lead Bullets
The first projectile to be fired from a rifled firearms was made of lead. The lead bullets held the field till the induction of smokeless powder. The smokeless powder generated higher velocities and higher temperatures. Lead bullets, though made from hardened alloy, started getting deformed under the conditions. The ballets consequently were not used in high velocity or semi-automatic or automatic weapons. The lead bullets however continue to be used in weapon firing law or medium velocities. The bullets for some revolvers, for example, are still made of lead alloy by some manufacturers
1.2 Jacketted Bullet
As seen above, smokeless powder increased the temperature and the velocities of the projectiles. It was found that lead bullets did not function properly at these velocities. They got deformed. Accuracy was adversely affected. To remedy this, the bullets were covered with a jacket. The coverage and the materials for the jacket varied tremendously. The commonest material for the jacket even today in copper.
Copper alloys and mild steel are also used as jacket materials. Previously there were ample variations in the jacketting patterns of the projectiles. Now complete jacketting is common in all the service rifle ammunition. There are, however, tremendous variations in the jacketting of the sporting rifle ammunition. The sporting rifles and their ammunitions are not common in India. They hardly figure in crimes in India.
1.2.1 Paper-Patch Bullet
The simplest material for the jacket was paper. Such bullets were known as paper-patch bullets. They were good. But they left pieces of paper in the barrel, which gave trouble in subsequent firing. The barrels had to be cleaned frequently. The bullets did not continue for long.
1.2.2 Wire-Patch Ballet
The next logical developmental jacket should have been a wire jacket. A lead bullet encased tightly in a wire spread over copper or some other material makes a wire-patch bullet. They were wire unbound itself. Both range and aim were adversely affected. They were soon given up. Some interest in wire-patch bullets has been aroused recently. A wire net in the shape of a bullet is placed in a bullet mould and molten metal is poured into the mould. The cast bullet is processed further as usual. They are likely to deformations at higher velocities and at higher temperatures.
1.2.3 Gas-Check Bullet
The base of a bullet comes in contact with hot gases. It is protected with a metal case in the gas-check bullet. The cover is made of copper usually. The bullets functioned well up to medium velocities.
The gas-check bullets are not encountered in India.
1.2.4 Electroplated Bullet
To prevent excessive deformation, lead bullets were electroplated with copper. However, the exercise did not give good results. They increased fouling of the barrel without reducing deformation of the bullets substantially, ultimately the method was given up mostly. 22 bullet are still copperplated by some manufacturers.
1.2.5 Metal Cased Bullet
The defects, which lead bullets suffered at high velocities, were almost fully overcome when they were covered by metal jackets. The jackets are varied in nature. They may cover the core completely, leave the nose exposed in soft nose and expanding bullets or leave the base exposed, as in most of the older military ammunition.
The material for jackets also varies Copper, brass, mild steel, cupro-nickel alloy and gilding metal are commonly used. Cupro-nickel is the favoured material but gilding metal is cheaper. The former contains copper and nickel and the latter, copper and zinc.
The thickness of the jacket varies somewhat with different manufacturers and sometimes at various parts, to achieve special effects. Often it is around 0.5 mm
In some cases the jackets carry cannelures are filled with grease and cartridge case is crimped upon them. The grease lubricates the bullet and reduces friction, in its passage through the barrel
In sporting rifle ammunition (excluding big game ammunition) the jackets, which permit expanding, to increase the wounding effect, are preferred. Ordinarily, expanding bullets mushroom or break up after their entry into a body. The expansion causes great tissue damage. The expanding effect is achieved in various ways :
(1) In Dum-Dum bullets the tip of the jacket was made thin by rubbing off the top.
(2) In soft or silver point nose bullets the tip of the bullet is made of softer material; brass and aluminum have been used.
(3) Hollow point bullets have hollow tips.
(4) Pierced point bullets have cuts on the upper part of the jacket
(5) Belted bullets have thinner jacket near the mid-point.
(6) The cup of the jacket contains a hard metal insert, a piece of steel or bronze.
The Dum Dum bullets were given the name because they were manufactured at Dum Dum. It is a place near Calcutta in India. The bullets were originally standard Mark VI 303 bullets. The British soldiers, who were fighting against Pathans, found that the bullets did not have sufficient stopping power. The soldiers rubbed the tips and softened them. On striking the target, these bullets with softened nose broke into many pieces and caused extensive injuries. They acquired tremendous stopping power and became popular. But the bullets were considered barbaric. The Hague Convention banned them. However, the fancy name stuck in some countries, where all expanding bullets are termed Dum Dum bullets.
Soft-point bullets are jacketted but the tip (the nose) is soft exposed, thin, made of softer material, have linear cuts. Hollow point bullets also behave like soft nose bullets. When the bullet strikes the target it mushrooms into an umbrella-like formation and causes a wound much larger in diameter than the bullet itself. Or. when the velocity is high, the bullet fragments cause extensive wounds. Thus, the stopping power and the wounding effect of the bullet is greatly increased.
The soft nose bullets are useful only for comparatively soft-skinned small animals. On tougher skins, they expand too soon. Consequently, the bullet may not penetrate and becomes ineffective. This defect is overcome in hollow point, silver tipped and belled bullets. They ensure both penetration and expansion.
In the hollow point bullets, the tip is hollow, the lead core does not fill the cone of the nose of the jacket. The bullet is excellent for aim accuracy and good for expansion.
The aluminium tipped bullets have aluminium in the tip of the jacket. The light weight metal for the tip improves the aim and range of the projectile. The British Mark VII bullet had an aluminium tip. In war days aluminium was replaced by paper, placed inside the jacket at the nose. The pierced tip bullets have the jackets cross cut at the tip. The cuts promote better expansion of the projectile
1.3 Non-Lead Bullet
The non-lead bullets were not common or popular, till recently. This is mainly due to the fact that the sectional density, considered an important factor in ballistics, is inadequate in other metals which are cheap and in abundance France did experiment with copper-zinc alloy bullets. It was called Balle D. It was not much of a success. Now, steel is being used increasingly as bullet material, either alone or in combination with lead. Bismuth and spent uranium are being used for pellets. The flechettes, the arrow-like projectiles for shotguns are made of steel. Copper is also being used for bullets.
1.4 Armour Piercing Bullet
Basically an armour piercing bullet consists of a hard tungsten-chrome steel core point at one end. It is enclosed in a mild steel jacket which has some space between the core and the jacket. The space is filled with a special filler alloy. On striking the target, the jacket and the filler create enough heat to soften the target material sufficiently to allow the core to enter into the target.
1.5 Tracer Bullet
The tracer bullets trace their trajectories, the path of flight. Some start tracing the path after traversing a distance of about 100 meters. The trace is visible in the form of a streak of bright red flame given by a special composition (Barium peroxide and magnesium powder) placed in the base of the bullet made hollow for the purpose. The bullet and other components of the cartridge are made to conform to the actual standard ammunition for which the trajectory is being observed.
The tracer ammunition is used to study the trajectories of similar standard ammunition. Theoretical considerations indicate that the results can be approximate only.
The tracer ammunition is available for machine guns, rifles and pistols. The cartridges are extremely dangerous and their dismantling should not be tried. They can start a fire if they strike or fall upon a combustible target
The tracer ammunition is encountered only rarely in crimes.
1.6 Incendiary Bullet
The incendiary bullets start fire on striking the target. The ammunition is extremely dangerous and needs extreme care in handling.
1.7 Boat-Tailed Bullet
The conical bullets were found to meet substantial air resistance at higher velocities. It was found that the resistance could be reduced if the base side of the bullet was tapered. The tapering (or boat-tailing) helped the flow of air over the bullet and reduced the air resistance.
The boat-tailing of the bullets improves the aim and the range of the projectiles considerably. It has been later found that greater the tapering greater is the reduction in air resistance. However, the tapering is limited to about the calibre length of the bullet. The limit is imposed so that the grooves grip the bullet properly to give it adequate rotation. It has been also found that the slant of about 9 of the boat-tail is adequate.
1.8 Stream-Lined Bullet
Stream-lined bullets were the logical development from the boat-tailed bullets. Here the tapering on both the nose and base sides ended in pencil points. Thus, the nose-side point helped smooth penetration of the air and the base-side point provided a smooth sliding surface for the air to flow over the bullet. The aim and range of these bullets, theoretically, should increase considerably.
The bullets as such would not fit in the barrel of the firearm properly. They are made slightly smaller in diameter than the diameter of the barrel. The bullet is fitted on to a sabot, a cylindrical piece, made of plastic or of wood. The sabot fits tightly in the barrel and spins, imparting spin to the bullet simultaneously. The sabot travels along with the projectile in the barrel and helps to keep it in position in the grooves. As soon as it comes out of the barrel, it gets separated from the bullet because of the air-resistance. Being made of lighter material, it soon falls off without creating any hindrance to the movement of the bullet.
These bullets require rigid constructional controls. The longitudinal axis must coincide with the line joining the end points. Besides, the centre of gravity must coincide with the centre of form (shape). Besides, the projectiles are too symmetrical to deform and to transfer its energy to the target. Consequently their effect is uncertain.
It is considered futile, ordinarily, to achieve range capability beyond 400 metres. The stream lined bullets have, therefore, not become.
1.9 Spherical Projectile
The spherical projectiles are still extensively used in shotguns, muskets, pest guns and other short range firearms. The shotgun is the principal weapon using spherical projectiles.
The spherical projectiles are made from hardened lead alloy (with antimony). They are used as single projectiles, as balls or slugs, or in larger numbers, in buckshot or pellet charges. The number of the pellets in a single cartridge can be over a thousand in some cases.
The balls, slugs and buckshot are cast in moulds. The molten lead is poured into the moulds, On cooling, the rough balls and buckshots are obtained. They are rumbled in barrels till the surfaces of the spheres become smooth. The manufacture of the pellets is different. Molten lead alloy is dropped through sieves from a height of about 50 to 75 metres in towers. The pellets are formed in the fall. They drop down in a water tank at the base of the tower. They are collected, rumbled and graded. The copper and nickel plated pellets have also been experimented with. They have not found favour on any extensive scale. Recently steel pellets have also been used for specific use.
A new process for the manufacture of spherical projectiles has also been developed. Lead alloy wires of appropriate size are cut into lengths of desired size and fed into dies. The dies compress and mould the slugs into spherical projectiles. Rounding and polishing are carried out as usual by rumbling.
The pellets other than lead or lead alloys are rare in India. But in some countries the following types of pellets are also manufactured:
1. Mild steel pellets. They are sometimes coated with copper or zinc.
2. Bismuth pellets – made of bismuth. They are sometimes coated.
3. Tungsten pellet.
4. Depleted uranium (DU) pellets.
These pellet materials have been used to overcome legal restriction for using the lead pellets for certain games. In India there is no such restriction so far. These non-lead projectiles do not offer any advantage in practice except that they are more humane to birds or animals. In fact they are inferior to lead pellets in some respects.
The smooth bore firearm projectiles can be divided into three categories:
1. Pellets
2. Buckshots
3. Ball
The cartridges bearing numbers 1 to 9 carry pellet charge. As the number increases the number of pellets also increases, and the pellets size decreases. The buckshot cartridges carry alphabetic lettering. Thus we have LG, SG, etc. The pellet charge is suitable for small bird game. The buckshot charge is used for bigger games.
The cartridges carrying ball ammunition has, usually, an exposed ball which can be seen easily. As already seen, the spherical projectiles are ballistically inefficient, especially at long ranges. Yet the shotgun is a popular firearm. To increase the aim and range of the firearm the following innovations have come up :-
(1) The Paradox projectile is a specially made bullet, (almost conical) intended to be fired from a paradox shotgun. The paradox shotguns have two shallow grooves rifled near the muzzle end. The paradox bullet, when passing through the grooved portion of the barrel, gets rotated which like bullets, continues to spin outside in the air. Both the aim and the range. are thus considerably improved.
(2) The Rotary projectiles are variously constructed. They have one thing common: they rotate as they move along the barrel. By the time the projectile is hurled out from the muzzle, the projectile acquires sufficient gyratory motion, which continues in its trajectory. The spin improves both the aim and the range of the shot.
The gyration of the projectile is achieved by special construction of the projectiles. They are often a hollow cylinder with fin-like twisted projections either on the inside or outside of the surface. The gases of combustion exert pressure on these fins and rotate the projectile. The hollow surface of the cylinder is covered in some ammunition with a wad to prevent escape of gases.
(3) The Split balls and buckshot packed in a spherical or cylindrical container are also used to increase the wounding effect of the ball ammunition.
The spherical lead balls have slightly less diameter than the bore diameter of the barrel from which they are fired.
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