Emilio Aguinaldo College

Manila
Criminology Review Center

A. What is BALLISTICS?
 In its broadest sense, ballistics is the science of the motion of projectiles. Science refers to the scientific study of
knowledge; motion refers to movement or mobility; and projectile refers to metallic or non-metallic objects
propelled from a firearm.
 In its narrowest sense or in brief and technically speaking, it refers to the science of firearms identification, which
involves the scientific examinations of ballistics exhibits.
 Is the science which deals with the study of conditions governing natural laws in relation to the performance of
gunpowder and projectiles in firearms.
B. What are the BRANCHES OF BALLISTICS?

1. Interior/Internal Ballistics - that branch of the science that has something to do with the properties and attributes of the
projectile while still inside the gun.
a. Firing pin hitting the primer
b. Ignition of the priming mixture
c. Combustion of the gun powder
d. Expansion of the heated gas
e. Pressure developed
f. Energy generated
g. Recoil of the gun
h. Velocity of bullet inside barrel
i. Rotation of the bullet inside bore
j. Engraving of the cylindrical surface of bullet
2. Exterior Ballistics – that branch of science, which has something to do with the attributes and movement of the bullet
after it has left the gun muzzle.
a. Muzzle blast – the noise created at muzzle point of the gun by reason of the sudden escape of the expanding gas
when it comes to instant contact with the air.
b. Muzzle energy – energy generated at muzzle point
c. Trajectory – the actual curved path of the bullet during its flight from the gun muzzle to the target.
d. Range – the straight distance between muzzle and target.
 Accurate (Effective) range – the distance within which the shooter has control of his shots.
 Maximum range – the farthest distance that a projectile can be propelled from a firearm.
e. Velocity – the rate of speed of the bullet per unit of time
f. Air resistance – resistance encountered by the bullet while in flight
g. Pull of gravity – downward reaction of the bullet towards earth center due to its weight
h. Penetration – depth of entry on target.
3. Terminal Ballistics – that branch of the science, which deals with the effects of the impact of the projectile on the target.
 Terminal Accuracy – size of the bullet grouping on the target
 Terminal Energy (Striking Energy) – energy of the projectile when it strikes the target.
 Terminal Velocity – speed of the bullet upon striking the target.

C. What is FORENSIC BALLISTICS

- is the study of the recovered projectiles to identify the firearms fired through them.
- The science that involves the investigation and identification of firearms by means of ammunition fired
through them. This science involves the following:
D. What is the ORIGIN OF FIREAMRS?
- Crude chemical mixtures resembling gunpowder are known to have been use in fireworks over 1000
years ago in China and India.
- Roger Bacon, an English monk was the first person to mention and record the formulation of true
gunpower, an intimate mixture of saltpetre, sulphur and charcoal, around the year 1248-1250.
- Berthold Schwartz, a German monk was credited with the application of gunpowder to the propelling
of a missile in the early 1300’s.
- The earliest firearms produces in Europe during the 14 th century were cannons and hand cannons:
simple tubes closed at one end except for a small touch-hole drilled into the breech end of the bore.
- The 15th century saw the development of SERPENTINE (match-lock) weaponry which allowed the
mechanical lowering of a smouldering nitrated cord or fuse into a pan of powder adjacent to the touch-hole.

- The 16th century saw the development of WHEEL-LOCK arms which utilized a serrated iron wheel
which was caused to rotate by clockwork against a piece of iron pyrites to produce a shower of sparks directed towards
the flash pan.
- The FLINT-LOCK IGNITION SYSTEM followed this development. In this system a flash pan was
attached to the side of the breech alongside the touch-hole leading to the main powder charge. A hinged cover, the
“frizzen” for the flash pan protected the priming powder charge and also served as a striking surface for the piece of
“knapped” flint held in the jaws of the hammer.
- The lock using this ignition system was seen in Spain around 1630 and was referred to as
“MIQULET-LOCK.” A similar system was seen in Holland around the same period and was referred to as the
“SPANHAUNCE-LOCK.”
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 - However, the main drawback with the flint-lock system were the slight delay between the primary
ignition and the firing of the main charge, misfire due to the use of poor quality flints, and the susceptibility of the
priming charge to the ingress of water during bad weather.

What is Percussion Ignition?

- The Reverend Alexander John Forsyth, a Scottish clergyman took out a patent dated April 11, 1807 that described the
application of sensitive chemical mixtures to allow their use in the exploding of gunpowder in firearms.
- During the 19th century percussion sensitive explosive mixtures were used to develop a range of new firing systems based
upon the percussion system. This material was used as priming pellets, in paper cap rolls, inside copper tubes, or within
copper caps which were placed upon a nipple screwed into the touch-hole at the breech end of the gun barrel.
- These percussion systems were superseded during the second half of the 19 th century by breech-loading arms utilizing
self-contained cartridges of needle-fire, pin-fire, rim-fire and center-fire design were then used with true breech-loading
arms. The era of the muzzle-loading arms ended.
- The needle-fire system was adopted by the Prussian armed forces in 1842 and proved to be extremely effective in the
Danish war of 1864 and further conflict in 1866 and 1870.
 With this system, their men could reload their weapons without the needed to stand up, as was
common practice with long-barreled muzzle-loading arms.The needle-fire cartridge utilized a nitrate paper
cartridge which could be pierced through its base by a long needle-shaped firing pin to fire the sensitive priming
patch fixed on the other side of the powder charge to a wad underneath the bullet. However, the long needle
striker was prone to corrosion and occasional breakage and a constant problem with gas leakage at the breech
end of the barrel.
E. What is a FIREARMS
 (legal definition, Sec. 877 RAC/Sec. 290 NIRC) – firearms as herein used, includes rifles, muskets,
carbines, shotguns, pistols, revolvers, and all other deadly weapons from which bullets, balls, shots, shells or other
missiles maybe discharged by means of gunpowder or other explosives. The barrel of any firearm shall be
considered a complete firearm for all purposes hereof.
- (Technical definition) – a firearm is an instrument used for the propulsion of projectiles by means of
the expansive force of gases coming from burning gunpowder.
- Means any pistols or revolver with a barrel less than twelve inches, any rifle with a barrel less than
fifteen inches, any shotgun with a barrel less than twenty-four inches, or any other weapon which is designed to
expel a projectiles by the action of an explosive.

What is a PISTOL?
– a short barrel hand arm designed to a fire a single projectile through a rifled-bore for every press of the trigger.
What is a REVOLVER?
– a hand firearm in which a rotating cylinder, serving as magazine, successively places cartridge into position for firing.
What is a Submachine gun?
- A submachine gun (SMG) is an automatic carbine, designed to fire pistol cartridges. It combines the
automatic fire of a machine gun with the cartridge of a pistol.
What is a MACHINE GUN?
– means any weapon, which shoots, or is designed to shoot automatically or semi-automatically, more than one shot,
without manual reloading by a single press of the trigger.
What is a Machine Pistol?
- A machine Pistol is a fully automatic pistol. It utilizes the same functions as a semi automatic pistol;
similar gas reaction pushed the hammer back continuously until the magazine is emptied. This usually requires the
fitting of a longer magazine or drum magazine.
What is a RIFLE?
- means any weapon designed or intended to be fired from the shoulder and make use of the energy of the explosive in a
fixed metallic cartridge to fire only a single projectile through the rifle bore for each pull of the trigger.

What is a SHOTGUN?
– is a smoothbore and breech loading shoulder arm designed to fire a number of lead pellets or shots in one cartridge.
F. What are the CLASSIFICATION OF FIREARMS
1. According to gun barrel construction
a. Smoothbore firearms – firearms that have no rifling inside their gun barrel.
b. Rifled-bore firearms – firearms that have rifling inside their gun barrel.
2. According to caliber of projectile propelled
a. Artillery – those types of firearms that propels projectiles more than one inch in diameter.
b. Small Arms – those type of firearms that propel projectiles less than one inch in diameter.
3. According to mechanical construction
a. Single shot rifle - has one firing chamber integral with the barrel which has to be manually loaded each time the
weapon is fired.
b. Repeating arms -
c. Bolt action type - A handle projects from a bolt. Pulling back and pushing forward on this projection cause the
bolt o extract and eject a cartridge case and then to insert a new cartridge while cocking the
gun.
d. Automatic loading type - the weapon fires, extracts, ejects, reloads, and cocks with each pull of the trigger using the
force of gas pressure or recoil to operate the action. After each shot the trigger must be
released and then pulled again to repeat the cycle.
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 e. Slide action type - loading takes place the forward-backward manipulation of the under forearm of the rifle.

f. Lever type (break-type) - the frame is hinged at the rear such that, on release of a top catch, the barrel swing down,
exposing the rear of the barrel for loading.

What are the 5 Categories of Small Arms

1. HANDGUNS - A handgun is a firearm designed to be held and operated by one hand.

a. Single-shot Pistols - a single-shot pistol is limited to one shot per firing cycle and has no reloading mechanism of
its own. It must be emptied and reloaded manually. Often, these weapons are of break type style, in which the
chamber is accessed by means of a hinged barrel, the muzzle of which is depressed during the breaking operation.
Modern single-shot pistols are use largely for competition target shooting.
b. Multi-barreled Pistols - is a firearm of any type with more than one barrel, usually to increase the rate of
fire/hitting probability and to reduce barrel erosion/overheating
 Derringers - they are a variant of single-shot pistols. Derringers are small pocket firearms with no magazine
and cylinder and have multiple barrels and each of which is loaded and fired separately. The traditional
derringers are single action and have two barrels with no trigger guard.
 Pepper box / pepper box revolver - is a multiple-barrel repeating firearm that has three or more barrels
grouped around a central axis. It mostly appears in the form of a multi-shot handheld firearm.
c. Harmonica Gun - is a form of percussion firearm which was breech loaded with a steel slide, containing a number
of chambers bored in it. Each chamber contained a separate primer, powder charge, and projectile. The slide was
inserted in an opening in the breech action and could be advanced by releasing the cam lock, moving the slide by
hand.
d. Revolvers - this is the most common type of handgun. Revolvers have a revolving cylinder that contains several
chambers each of which holds one cartridge.
Revolvers may either be single-action or double action types. In single-action revolvers, the hammer
revolves manually each time the weapon is to be fired. Cocking the hammer revolves the cylinder, aligning the
chamber with the barrel and the firing pin. In double-action revolvers, a continuous pressure on the trigger revolves
the cylinder, aligns the chamber with the barrel, and cocks and then releases the hammer, firing the weapon. The
visible parts of the revolver are shown in figure 6. There are three types of revolvers:
a. Swing-out – on pressing the cylinder latch, normally found on the left side of the frame and pushing the
cylinder to the left, the cylinder swing-out, exposing the chambers. Each individual chamber is then loaded
with a cartridge. The cylinder is then swung back into the frame.
b. Break-top Revolvers – the frame is hinged at the rear such that, on release of the top catch, the barrel and
cylinder swing down, exposing the back of the cylinder for loading. The opening action will also eject empty
cases from the cylinder. This form of revolver is the traditional form in Great Britain.
c. Solid-Frame Revolver – this is the oldest form of revolver dating to Colt’s original weapons. In this weapon,
the cylinder is held in the frame by a certain pin, around which it rotates. The back of this cylinder is never
exposed completely by either “swinging out” or “breaking open.” Each chamber in cylinder is loaded
individually through a loading gate on the right side of the frame.
e. Semi-automatic pistols - is defines as a handgun that contains only a single chamber, but has an automatic
mechanism to remove an empty casing from the chamber and insert a new cartridge from the magazine.
Borchardt produced the first commercial automatic pistol in 1893, this weapon was the predecessor of the
Luger. There are four (4) methods of operation of automatic pistols to day:
1. Blowback - the pressure of the gas produced by combustion of the powder forces an unlocked slide to the rear, thus
starting the cycle of extraction, ejection, and reloading.
2. Delayed or retarded blowback – on firing the gun, part of the propellant gas is directed through a small bent in the
barrel ahead of the chamber into a cylinder beneath the barrel. A piston attached to the slide enters the front end of
this cylinder.
3. Recoil – the barrel and the slide are locked together at the moment of firing. As the bullet leaves the barrel, the
rearward thrust of the propellant gas on the cartridge case starts the slide to move to the rear. After a short distance,
the barrel is halted, and the locking device is withdrawn from the slide. The slide then continues to the rear, ejecting
the case and starting the reloading cycle.
4. Gas - a portion of high-pressure gas from the cartridge being fired is used to power a mechanism to extract the spent
case and chamber a new cartridge. Energy from the gas is harnessed through either a port in the barrel or trap at the
muzzle. This high-pressure gas impinges on a surface such as a piston head to provide motion for unlocking of the
action, extraction of the spent case, ejection, cocking of the hammer or striker, chambering of a fresh cartridge, and
locking of the action.
2. Rifles
A rifle is a firearm with a rifled barrel, which is design to be fired from the shoulder. Automatic Rifle is one that on
pulling the trigger and firing the weapon utilizes the force of gas pressure or to recoil to eject the fired case, load the next
round, fire, it, and then eject it.
An “assault rifle” refers to a rifle that is:
a. Auto-loading
b. Has a large capacity (20 rounds or more) detachable magazine
c. Is capable of full-automatic fire
d. Fires an intermediate rifle cartridge
3. Shotgun

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 A shotgun is a weapon intended to be fired from the shoulder; it has a smoothbore and is designed to fire multiple
pellets from the barrel.

4. Submachine Gun
A submachine gun or machine pistol is a weapon that is designed to be fired from either the shoulder and or hip, is
capable of full0automatic fire; has rifled barrel and fires pistol ammunition.
5. Machine Gun
A machine gun is a weapon that is capable of full-automatic firing and that fires rifle ammunition.
 Gatling Gun - one of the best-known early rapid-fire weapons and a forerunner of the modern machine gun. The
Gatling gun's operation centered on a cyclic multi-barrel design which facilitated cooling and synchronized the
firing/reloading sequence. Each barrel fired a single shot when it reached a certain point in the cycle, after
which it ejected the spent cartridge, loaded a new round, and in the process, cooled down somewhat. This
configuration allowed higher rates of fire to be achieved without the barrel overheating.
Three Classification of Machine Gun
a. Light machine gun (LMG) - is a machine gun designed to be employed by an individual soldier, with or
without an assistant, as an infantry support weapon. Light machine guns are often used as squad automatic
weapons.
b. Medium machine gun (MMG) - in modern terms, usually refers to a belt-fed automatic firearm firing a full-
power rifle cartridge.
c. Heavy machine gun (HMG) - is a larger class of machine gun generally .50 or 12.7mm machine guns
pioneered by John Moses Browning with the M2 machine gun and designed to provide an increased degree of
range, penetration and destructive power against vehicles, buildings, aircraft and light fortifications over the
standard rifle calibers used in medium or general purpose machine guns.
6. Multi-barrel Firearms
Rifles and shotguns containing multiple barrels are some of the oldest types of multi-shot firearms, and their use
continues to this day. These guns are traditionally used for hunting fast-moving or dangerous game, as the simplicity of the
design makes a rapid second shot quick and certain; double rifles are known as express rifles or when combined shotgun with
rifle, are known as drilling or more accurately combination gun (the term "drilling" is German), the original "combination"
guns manufactured in Europe had three bores over posed, but could be fashioned in more or less.
 Volley Gun –is a gun with several barrels for firing a number of shots simultaneously or fires their barrels in
sequence. They differ from modern machine guns in that they lack automatic loading and automatic fire and are
limited by the number of barrels bundled together.
G. What is AMMUNITION?
(Sec. 877 RAC) – it means loaded shell for rifles, muskets, carbines, shotguns, revolvers, and pistols from which a
ball, bullet, shot, shell, or other missile maybe fired by means of gunpowder or other explosives.
(Technical definition) – refers to a group of cartridges or to a single unit or single cartridge, a complete unfired unit
consisting of bullet, cartridge case, gunpowder and primer.
What are the PARTS OF A CARTRIDGE?
1. Bullet 3. Gunpowder
2. Cartridge case 4. Primer
H. What is the CLASSIFICATION OF CARTRIDGE?
1. According to location of primer
 Pin-fire cartridge
 Rim-fire cartridge
 Center-fire cartridge
2. According to caliber
Cal. 22 - 5.56mm
Cal. 25 - 6.35mm
Cal. 32 - 8.13mm
Cal. 357 - 9.07mm
Cal. 38 - 9.65mm
Cal. 380 - 9.65mm
Cal. 40 - 10.16mm
Cal. 44 - 11.17mm
Cal. 50 - 12.7 mm
I. What is a BULLET
– is a metallic or non-metallic cylindrical projectile propelled from a firearm by means of the expansive force of gases
coming from burning gunpowder.
What are the CLASSIFICATION OF BULLET
1. According to mechanical construction
 Lead – those that are made of lead of alloys of this metal, lean tin, and antimony that is slightly harder than pure lead.
 Jacketed – those with a lead core of lead alloy covered by a jacket which is harder metal such as gliding metal, a
copper zinc, alloy of approximately 90% metal.
3. According to form and shape
 Wad-cutter
 Flat noise
 Pointed
 Semi-wad
 Hollow point (dum-dum bullet)

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  Soft point
 Round nose
 Hollow base

What are the PARTS OF A BULLET

1. Nose or ogive
2. Cannelure to hold the lubricant
3. Base
4. Knurling to hold the jacket or serves as the distinctive patter of the manufacturer.
J. What is a CATRIDGE CASE – is a tubular metallic or non-metallic container that holds together the, bullet, gunpowder, and
the primer.
FUNCTION OF A CARTRDIGE CASE
1. It serves as means whereby the bullet, gunpowder, and primer are assembled into a unit.
2. It serves as a waterproof container for the gunpowder.
3. It prevents the escape of the gases to the rear as the sidewalls of the cartridge case are forced against the walls of the
chamber by the pressure.
What are the PARTS OF THE CARTRDIGE CASE
a. Rim – the projecting rims of rimmed and semi-rimmed cases serve the purpose of limiting the
forward travel of the cartridge into the chambers and thus also limit the clearance, if any, between the heads and
the supporting surface of the bolt or breechblock.
b. Head and Body – this part constitute the cork that plugs the breech of the barrel against the escape
of the gas.
c. Neck – the term “neck” is applied to that part of the cartridge case that is occupied by the bullet. In
cases of bottleneck form, the neck is apparent but in so-called “straight cases that have only a slight taper, it is
not.
d. Shoulder – that portion which supports the neck.
e. Cannelures – shell cannelures are the serrated grooves that are sometimes found rolled into the
necks and bodies of the cases at the location of the bullet bases to prevent the bullets from being pushed back or
loosened.
f. Crimp – the crimp is that par of the mouth of a case that is tuned in upon the bullet. Its functions
are two-fold: (a) it aids in holding the bullet in place, and (b) it offers resistance to the movement of the bullet
out of the neck that affects the burning of the gunpowder.
What are the Three Types of Crimps
 Roll Crimp – the case is literally rolled either into the bullet material or a groove in the bullet to
secure it. Rolled crimp are primarily used on cartridges that headspace on the rim or case
shoulder.
 Taper Crimp – is used primarily with cartridge that headspace on the case mouth with lead bullets.
With a taper crimp the mouth of the case run into a die with a taper opening that squeezes the
diameter of the neck down enough to grip the bullet securely but still leaves enough metal to
headspace on the chamber.
 Stab or Ring Crimp – used only in jacket ammunition, consists either severally impressed dimples
or grooves pressed onto the case mouth by a collets. This crimp can either enter a groove on the
bullet or can just be pressed into the bullet body. It is primarily used in commercial heavy caliber
hunting ammunition where rough handling may be encountered.
g. Extracting grooves – the circular groove near the base of the case or shell designed for the
automatic withdrawal of the case after each firing.
h. Base – the bottom portion of the case, which contains the (a) primer and the shell head.
i. Primer pocket – primer pocket perform the triple functions of:
 Holding primer securely in central position.
 Providing a means to prevent the escape of gas to the rear of the cartridge.
 Providing a solid support for primer anvils, without which the latter could not be fired.
There are two types of primer pockets:
 Berdan Primer Pocket – a primer pocket that has two flash holes. European metallic cartridges
traditionally are loaded with berdan primer pocket. It has no integral anvil; the anvil is built into the
cartridge case and forms a projection in the primer pocket.
 Boxer Primer Pocket – consists of a brass or gilding metal cup, a pellet containing a sensitive
explosive, a paper disk and a brass anvil. The boxer primer pocket has a single flash hole in the
bottom of the case.
j. Vents or Flash Hole – this is the connecting hole between the primer and the gunpowder.
What are the Three General Shapes of Cartridge Cases
a. Straight – this type of cartridge case has no visible neck. Usually pistols and revolver cartridge utilize this type.
b. Bottleneck – this design permits more powder to be packed in a shorter, fatter cartridge than would possible in a
straight cartridge. Rifles cartridges used this type.
c. Tapered – although considered obsolete, this was present in the so-called “magnum jet” cartridge in caliber .22.

What are the Classification of Cartridge According to Head Form

a. Rimmed – have an extractor flange that is larger in diameter of the cartridge case body.
b. Semi-rimmed – have an extractor flange that is larger in diameter than the cartridge case body, but they also
have a groove around the case body just in front of the flange.

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 c. Rimless – Have an extractor flange whose diameter is the same as that of the cartridge case body and also
have a groove around the body of the case in front of the flange.
d. Rebated – has an exterior flange that is smaller than the diameter of the case. A groove around the body of
the case is present in front of the flange.
K. What is a PRIMER – is that portion of the cartridge which consists of a brass or gliding metal-cup containing a highly
sensitive mixture of chemical compound, which when struck by the firing pin would detonate or ignite.

What are the TWO (2) TYPES OF PRIMER POCKET

1. Boxer type – with only one flash hole
2. Berdan Type – with two flash holes
What are the PARTS OF THE PRIMER
1. Primer Cup
2. Priming mixture
3. Anvil
4. Disc
What are the TWO FOLD PURPOSE OF THE DISC
1. To hold the priming mixture in place
2. To exclude moisture
L. What is a GUNPOWDER (propellant or powder charge) – refers to the propellant which, when ignited by the primer flash, is
converted to gas under high pressure and this propels the bullet or shot charge through the barrel.
What are the CLASSIFICATION OF GUNPOWDER
1. Black Powder – it is the oldest of all the propellant. It consists of irregular grains which when fired produces large
volumes of grayish smoke and considerable residue is left in the barrel.
2. Smokeless Powder – the most commonly used powder in modern ammunition. The most powerful of the propellants.
What are the FOUR MAIN CLASSES OF SMOKELESS GUNPOWDER
1. Single-base propellant – contains only pure nitroglycerine geletanized with nitrocellulose.
2. Double-base propellant – are those having nitrocellulose and nitroglycerine as their major ingredients, accompanied by
one or two minor ingredients such as centralite, vaseline phthalate esters, inorganic salts.
3. Triple Base propellant – is a type of propellant powder which uses three principal ingredients:
 Nitrocellulose
 Nitroglycerine
 Nitro-guanidine- lowers the flame temperature while adding active explosive constituent.
4. High-Ignition propellant – is a type of propellant in which the main constituents is from RDX group of high explosives.
It was moderated to the process of gelatinization and was then developed by the Dynamit Noble of Germany in
conjunction of Heckler and Koch for the lather’s G11K2 rifle. This is caseless ammunition.
M. What is a TOOLMARKS - is a mark resulting from contact between a tool and the surface of some object. When two
surfaces are brought into contact with sufficient pressure, the harder one will scratch or made an impression of itself on the
softer surface.
What are the Two Types of Toolmarks
1. Indented Mark - is made by forcing a tool against the surface of an object and applying sufficient pressure to leave a
negative impression of some aspect of the tool on the surface. (Impression or Compression are other terms referring to
indented mark)
2. Straited Mark - is produce when a tool is placed against an object surface that is softer than the tool, pressure is applied
and the tool is moved across the surface.
LABORATORY EXAMINATION OF TOOLMARK
Laboratory examination of tool mark evidence can yield information about:
 The type of tool used;
 The size of the marking portion of the tool;
 Any unusual features of the tool;
 The action by which the tool made the mark; and
 A conclusion as to whether a particular suspected tool made the specific marks.
As with any examination of physical object, the basic elements in a toolmark examination and comparison are:
 Reproduction of test marks in a manner resembling the questioned mark as closely as possible; (test marks
produced at slightly different angles or directions can result in marks that are completely dissimilar).
 Comparison of the striations, damaged areas and other characteristics of the test mark with those of the
questioned mark.
N. FIREARMS IDENTIFICATION
What is BULLET IDENTIFICATION?
The examination of firearm evidence constitutes one of the more important phases of police laboratory, firearms
identification. When a bullet, either plain lead or jacketed, passes through a rifled barrel under high pressure, the bullet tends
to expand and fill the whole cross section of the barrel. The bullet should be of such size that it does this, in order to follow
the rifling, as it should to prevent loss of pressure, and to prevent erosion of the inner surfaces of the barrel by escaping gases.
The more completely the bullet fills the cross section of the barrel the more distinctive the markings will be and the
better the matching of the rifling marks. Rifling the spiral grooves inside the gun barrel that is responsible for the rotation of
the bullet during its flight towards the target. The Rifling is composed of the Lands (the elevated portion) and the Grooves
(the depressed portion). This is made through a process called “rifling method” wherein the grooves are scrape from the
bore of the barrel. Inequalities in the steel surfaces of both lands and grooves will then score the bullet as it passes through
the barrel under pressure, and it will show useful markings for identification.
What are four (4) methods commonly used in making the rifling?

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 a. Scrape Cutter – this consists of a rod, slightly smaller that the bore of the gun, into which is a set either one or two
curved hardened steel scrapers the height of which can be adjusted between successive passages through the barrel. The
cutting edges of the hook, which has been filed to exact dimensions, projects through a slot in a rod (Fig.5).
b. Hook Cutter – a cutter with the general shape of a crochet-hook is set into a recess or slot in a rod, which is a bit smaller
than the bore of the barrel. The height of the cutting edge of the “hook” can be adjusted by turning an adjusting screw at
the end of the rod.

c. Broaching Method – this consists of a rod upon which there are 25 to 30 hardened steel rings, each one being slightly
greater in diameter than the preceding one and having slots of the proper size cut into it at equal interval, thus, forming a
series of cutters.
d. Swaging or Button Methods – this consists of a “plug” of extreme hardness and is forced through a barrel, the bore of
which is slightly smaller than the button tool. The metal of the barrel flows slightly under this very high pressure and the
bore is slightly increased. The tool has a torpedo-shaped button made of tungsten carbine or other similar material of
extreme hardness that is provided with lands and grooves that are in the negative of those produces in the barrel .

What are MARKS FOUND ON BULLETS?

There are a number of marks found on fired bullets that are useful in its identification, these are:
1. Land Marks - this is cause by the lands inside the barrel.
2. Groove Marks - this is cause by the grooves inside the barrel.
3. Skid or Slippage Marks - this is cause by bullet jumping the rifling.
4. Stripping Mark - this is cause when the bullet is moving with a motion of transition accompanied by a motion of
rotation less than that provided for by the rifling. (worn-out barrel)
5. Marks made by the Forcing Cone - this is made when the bullet strikes the forcing cone and by irregularities that
exist at the muzzle.
CLASS AND INDIVIDUAL CHARACTERISITCS OF MARKINGS

Markings found bullets and cartridge cases falls under two general categories, namely:

1. What is a CLASS CHARACTERISTICS? – are those characteristics, which are common to a group of
firearms.

What are the different class characteristics of a firearms?

a. Bore Diameter and caliber – the caliber refers to the diameter of the bore, which is measured from two
opposite lands.
b. Number of lands and grooves – the number of lands and the grooves in a given weapon are always the same.
If the bore has six grooves, it will also have six lands.
c. Directions of rifling twist – Direction of twist is only of two possibilities, left and right hand twist. (Colt has a
left hand twist, S&W has a right hand twist). The purpose of the twist if provide “bite” into a bullet and cause it to rotate
as it passes through the bore.
d. Widths of lands and grooves – The widths of lands and grooves show a great variation, even for guns having
the same numbers of grooves. The width of land in a gun can be determined by measuring the width of its impressions
on a bullet passed through it. The width of a groove in the gun cannot be so determined because the whole cross-section
of the land in a gun is usually wedged shaped in cross section.
e. Degree of twist of rifling (Pitch) – this is the measure of the twisting of the lands and grooves. It is the barrel
length required for a groove or land to make one complete revolution.
f. Depth of grooves – groove depth in the bore is measured on a radius of the bore as seen in cross-section.
Grooves are usually a few thousandths of an inch deep. However, this has little application to the problem of
identification of a firearm.

2. INDIVIDUAL CHARACTERISTICS –
 are those characteristics, which are unique to a particular firearm and is likely to e repeated.
 The individual characteristics on a fired bullet are those features, which distinguish it from bullet fire through
all other bores.
 Practically speaking, the term applies to those minute striae along the land and groove impressions that are
produce by, and are characteristics of, irregularities within a given bore.
 These individual characteristics are determinable only after the manufacture of the firearm.
 They are characteristics whose existence is beyond the control of man and that have random distribution inside
the gun.
 here existence in a firearm is brought about by the tools used in their manufacture.

What are the PRINCIPLES INVOLVED IN FIREARMS IDENTIFICATION?

The Principles involved in the examination of firearms is summarized as follows:

a. Firearm identification is actually a refined toolmark identification;

b. The natural wear and tear of the tools involved;
c. When a softer surface comes in contact with a harder surface, it is the softer surface that will acquire or be engraved or
marked with impressions or scratches from any irregularities on the harder surface; and
d. The fact that no two things are absolutely identical or alike.
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IDENTIFICATION PROCEDURE

The identification procedures followed in the comparison of minute characteristics are essentially the same as those
utilized in toolmark identification. They only differ only to the extent that the general features of fired bullets are unlike the
ordinary tool-marked surfaces. In examining bullets one is in effect examining a number of different tool marks on one
object. These toolmarks vary considerably along their length at times, and assume various angular positions with respect to
one another.

Each separate land impression or groove impression may be regarded as a separate tool mark to be compared.
Altogether, one might image the bullet as a single object bearing perhaps eighteen or twenty “independent” tool markings.
Within each of these areas, individual striae must examine. Since the specimen is roughly cylindrical, but a few of these
marked areas are visible at any one time, so the specimens must be rotated to various orientations in the comparison process.

What are the steps in the Identification of Bullets?

 A submitted firearm will be fired several times using a water tank like the one on the left to obtain standards from the
firearm.
 Lids on the tank are closed and locked and the muzzle of the firearm is placed in the open tube at the end of the tank and
fired. Friction from passing through the water slows the bullets down and they end up on the bottom of the tank about
halfway down its length.
 The tank is approximately 3 feet wide, 10 feet long, and 3 feet high.
 Fired standards, are examined first to determine if in fact the barrel is producing microscopic marks and if so does a unique
and consistent pattern to the marks exist.
 Once a consistently reoccurring pattern to the marks is identified on standards, the standards are compared to the evidence
bullets to see if the same pattern of marks exists on the evidence.
 To make these comparisons the firearm examiner will use a comparison microscope.
 One of the first steps taken in the comparison is the general alignment of the test and evidence bullets on the comparison
microscope.
 All firearm sections will have a comparison microscope.
 The two specimens are then rotated until one or more unusual or “characteristics” area is located.
 Once a region for identification is identified, it is then held at that position while the other is rotated until a matching region is
found.
 If there is no such matching area is found, another outstanding or peculiarly recognizable area is sought on, one specimen and
again the second bullet is rotated in search of a match region.
 The procedure continues until a similarity or “match” in the two is found, or until all areas on both bullets have been
exhaustively compared.
 During this comparison the bullets are frequently shifted laterally so that different positions along the length of the specimens
may be compared as well as different positions around the periphery.
 If this process finds similar or matching areas, the two bullets are then considered being “in phase” and thereafter, both are
rotated together and at the same rate to hold them constantly in “phase.”
 Individual striae and striated areas are compared throughout the complete periphery and various lengthwise positions.

What is a Comparison microscope?

 The comparison microscope consists of two microscopes mounted side by side and connected by an optical bridge.
 There are two stages on the lower part of the microscope that the bullets to be compared are mounted on. The bullets are
attached to the stages using some type of sticky substance.
 Images of the bullets travel up through the objectives, bounce off several mirrors in the optical bridge, and are combined in a
round field of view seen by looking into the stereoscopic eyepieces.
 The resulting image will show the bullets mounted to the stages, side-by-side, with a thin dividing line down the middle.

B. What is CARTRDIGE CASE IDENTIFICATION?

Cartridges, especially those fired in automatic o repeating firearms, often show repetitive marks that are useful in the
identification of the type of weapon used. Impressions that are made by the file marks, tool marks or other inequalities on the surface
of the breechblock when a shell sets back against it under high pressure are likely to be more reproducible than marks made by the
rifled bore

The size, shape, and location of extractor and ejector marks the type of breechface mark, the presence of magazine scratches,
etc. are all important in helping to determine the type used. The individual weapon in which a cartridge was fired can often be
determined by comparison of the markings on evidence shell with those produced by the suspect firearm on test shells.

An important consideration in cartridge case identification is the same make of ammunition be used as that in the evidence
submitted. In fact, it is even more important here than in the case of bullet comparisons, because small difference in thickness or in
the composition of the primer or in the composition of the brass of the shell head will make marked difference in the distinctness of
the marks produce. However, if reproducible and matching marks are not present on test shells, it is quite proper to use other
cartridge, because if the marks on the evidence shell can be reproduced on any ammunition it is sufficient proof that one has the right
gun.

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What are the MARKS FOUND OF CARTRDIGE CASES?

1. Firing Pin mark - the firing pin of a weapon is little more than a metal rod or projection which is thrust
against the primer of a cartridge by spring pressure. The firing pin mark usually shows impressed striae in circular rings, straight
lines of unusual formations of all types. Firing pin just like rifling has individuality that can differentiate one firing pin from
another. The chance that two firing pins will chip in precisely the same way is very remote.

In arms designed to fire center-fire cartridges, the end of this pin is rounded off so that it makes a generally
hemispherical depression in the primer. Weapons firing rim-fire cartridges more often have a pin that is flat on the striking end.
Generally there are five basic shapes of rim-fire firing pin:

a. Bar d. Semicircular
b. Rectangular e. Special
c. Round

2. Breech face Marks - Breechface marks are made by the impact of the shell head against the breechblock by
the force of the explosion in the cartridge. The pressure that drives the case against the breechblock usually measures up to
65,000 pounds per square inch. And since the pressure is exerted equally in all directions, it is obvious that the shell case will be
pushed back against the breechblock with considerable force as to leave a distinct and comparable markings.

3. Extractor Marks - extractors marks made by automatic and repeating firearms can frequently be matched and
often very effectively. In repeating guns, the depth of the impressions will vary considerably, depending on the vigor of the
operator. In some automatics firearms, the location of the extractor is at the top of the chamber so that it marks the cartridge at 12
O’clock position. More commonly, it is produces a mark at 3 O’clock position.

4. Ejector Mark - ejector mark does not always leave a clearly discernable mark on the cartridge head. When
both the extractor and ejector mark are visible, they serve to indicate certain class characteristics of the weapon.

5. Clip Marks - the clip or magazine for an automatic pistol is an elongated metal box, open at the top and fitted
with a spring mechanism which pushes the cartridges upward. The top is wide open at the forward end to permit loading, but
provided with lips at the rear which keep the cartridge in place and guide them up and out as the gun operates.

6. Shearing Mark – these are considered as “secondary firing pin mark.” They are found next to the firing pin
mark.

7. Chamber-produced marks – marks produced on cartridge cases by the chamber assume various forms. When
a cartridge is inserted into the chamber, the casing may be scratched lengthwise by minute imperfections around the mount of the
chamber.

IMPORTANT NAMES IN BALLISTICS

1. Browing, John - Wizard of modern firearm and pioneered breech loading single shot firearm
2. Colt, Samuel - Produces the first practical revolver
3. Deringer, Henry - He gave his name to a whole class of firearm
4. Forsyth, Alexander John - Father of percussion ignition
5. Garand, John - Designed and invented the semi-automatic US rifle (cal. 30M1)
6. Goddard, Calvin H. - Father of modern Ballistics
7. Marlin. John Mahlon - Founder of Marlin Firearms Company
8. Remington, Eliphalet - One of the first makers of rifles
9. Ripley, James Wolfe - Stimulated the development of the model 1855 rifled musket
10. Root, Elisha King - Designed machinery for making Colt firearms
11. Smith, Horace - Founded the great firm Smith & Wesson and pioneered the making of breech-loading
rifles
12. Thompson, John - Pioneered the making of Thompson submachine gun
13. Wesson, Daniel - partner of Smith in revolver making
14. Williams, “Carbine” David - Maker of the first known carbine
15. Winchester, Oliver - One of the oldest rifle and pistol makers

IMPORTANT DATES IN BALLISTICS

1. 1313 - The age of gunpowder began with its Forsyth use as a propellant for a projectile.
2. 1350 - Small arms. In this Century, portable hand firearms were introduced.
3. 1498 - Riflings. The year when the first reference to riflings appeared.
4. 1575 - Cartridge. Paper cartridge combining both powder and ball were developed.
5. 1807 - Percussion system. The discovery by Forsyth that certain compounds detonates by a
blow could be use to ignites the powder harge of a firearm.
6. 1836 - Pin-fire Cartridge. The pinfire cartrdige developed by Le Faucheux was probably the
first self-exploding cartrdige to come into general use.
7. 1845 - Rimfire Cartrdige. In France Flobert developed a bullte breech cap which was in reality
the first rimfire cartridge.
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 8. 1858 - Center-fire. The morse catrdige of 1858 marked the beginning of the rapid development
of the center-fire cartridge.
9. 1884 - Automatic Machine gun. Hiram built the first fully automatic gun, utilizing the recoil of
the piece to load and fire the next charge.
10. 1885 - Smokeless powder. In France, Vieille developed the first satisfactory smokeless
powder.

RIFLING CHARACTERISTICS OF RILFES AND HANDGUNS

Caliber Manufacturer Direction of Twist No. of Lands and

Grooves
Handguns
Colt, Beretta, Browning, L 06
.22 S, L, LR Smith &Wesson, Ruger R 06
Pheonix, Jennings R 16

Colt L 06
.22 Magnum Ruger, Smith & Wesson, Rohm R 06
.25 Colt, Astra, Raven, Davis L 06
Titan, Beretta, Browning R 06

Colt, Davis 06
.32 Browning, Beretta, Lorcin R 06
Walther, Sig-Sauer

Colt, Davis L 06
.380 Browning, Beretta, Lorcin R 06
Walther, Sig-Sauer

Smith & Wesson R 05

Colt L 06
9 mm Parabellum Browning, Walther, Taurus, R 06
Beretta, Glock, Sig-Sauer, H&K,
Lorcin

Colt, Miroku L 06
Smith & Wesson, Taurus, Ruger R 05
.38 Special D.A.
Colt MK III, Rossi, Taurus R 08
Arminius, Rohm,
Colt L 06
S & W, Ruger DA, Taurus R 05
.357 Magnum Colt MK III, Dan Wesson, Ruger R 06
SA/DA

S&W L 06
.40 Magnum Beretta, Glock, Star Taurus, R 06
Astra, H & K , Ruger

.41 Magnum S&W R 05

Ruger R 06

.44 Magnum S&W R 05

Ruger SA R 06

.45 Colt, Sig-Sauer L 06

Star, llama. S & W R 06

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