6-7 Flashcards
It is a small container or wafer of explosive material used to ignite the gunpowder
primer
The upper portion of the primer cup which is the complete assembly of priming composition,
paper disk, anvil and vent.
primer.true
Contains a highly sensitive mixture of chemical compound which when struck by the firing pin
would detonate or ignite
primer
the process where chemical compound when struck by the firing pin would detonate or ignite
percussion
Large Rifle and Large Pistol
.210 inches
Small Rifle and Small Pistol
.175 inches
Composition of Priming Mixture
- Potassium Chlorate – 45 %
- Antimony Sulfite – 23%
- Fulminate Mercury – 32%
– the first to conceive an idea of using a detonating compound for igniting
powder charge in small arms by percussion, and obtained a patent for this idea.
- He was then considered as the Father of Percussion.
Alexander John Forsyth
has ONE vent/flash hole invented by Colonel Edward M. Boxer, a British Army
Boxer primer
has TWO vents/ flash holes, invented by Colonel Hiram Berdan, a US Army
Berdan Primer
has THREE vents/flash holes.
. Berdan-Boxer Primer
used for shotgun shells, a variation of Berdan.
Battery Cup type
Two Classes of Priming Compound
- Corrosive – early primers
- Non-corrosive – mostly used at present
where the priming mixture is crushed by blow from the firing pin
anvil
a highly sensitive mixture of chemical compound contained in the primer
cup.
Priming Mixture
piece of small paper or disk of tin foil that contains the priming mixture that is being
pressed over the anvil.
It has 2 purposes:
1) To hold priming mixture in place and
2) To exclude
moisture.
disc
container of the anvil, disc and priming mixture. This is made of brass, gilding
metal or copper
Primer Cup
set off with a sharp blow, as when the firing pin strikes the primer
cup.
. Initiator (Lead Styphnate)
– gives up its oxygen readily. The oxygen is needed to burn the fuel
Oxidizer (Barium Nitrate)
burns the gunpowder in a very high rate results to the propulsion of bullet.
Fuel (Antimony Sulfide)
in order to fire before, the gunpowder must have to be ignited
Igniting the Propellant
the earliest firearms which use closed tubes, that need manual ignition of its
gunpowder
cannons
a small aperture drilled in the closed end of the tube, leading to the main
powder charge.
touchhole
touchhole was filled with finely ground powder, which was then ignited with a hot
ember
or torch.
external priming
Wheel-lock
Flintlock
Caplock
Electric-fired
around the rim
Rimfire
external pin is used in igniting the priming mixture
Pinfire
combination of rim and pinfire, uses a pin that strikes a ring of a priming
compound.
Peripheral primer
primer is located at the center.
Centerfire
– no rim. rounded at the rear, with a small “teat” that would protrude through a tiny
opening in the rear of the cylinder.
teat-fire
Used by larger military guns and cannon rounds (such as the M50 20mm) utilize
an internal electric primer that is activated by an externally-provided electric charge.
Electric-primed
The powder that is used in ammunition in the propulsion of projectile.
Gunpowder (powder charge, propellant, saltpeter, cordite, etc)
Gunpowder in the 19th Century was known as
The first known chemical explosives until
1800s.
Considered the oldest propellant.
Black Powder
It is a mixture of sulfur, charcoal, and potassium nitrate (saltpeter) - with the sulfur and charcoal acting as
fuels, while the saltpeter works as an oxidizer.
Black Powder
the unrecognized inventor of gunpowder.
Wu Ching Tsun
an English monk and scientist, credited with the invention of gunpowder
(blackpowder).
Roger Bacon (1248)
A German monk was credited for the
application of gunpowder for propelling missile.
Constantine Anklitzen (a.k.a. Berthold Schwartz) (1300)
invented smokeless gunpowder with nitrocellulose, a single-base propellant which
was called Poudre B (composition of ether and alcohol).
Paul Vielle (1886)
developed smokeless gunpowder and he called it Ballistite, a double-base propellant.
Alfred E. Nobel
obtained a patent of modifying smokeless gunpowder, they called it Cordite.
Frederick Abel & James Dewar (1890)
Black Powder – consists of jet black and shiny grains.
Composed of:
A. Potassium Nitrate – 75%
B. Charcoal – 15%
C. Sulfur – 10%
Smokeless Powder – produces a small amount of smoke.
Composed of:
A. Nitrocellulose – 60 parts
B. Nitroglycerine – 35 parts
C. Vaseline – 5 parts
is the principal ingredient of smokeless powder, invented in 1846.
Guncotton
have SLOW burning gunpowder
Long Arms
have FAST burning gunpowder.
Short Arms
The 1st examination and detection of GSR was done.
1911
Dr. Iturriuz was the 1 st to use Paraffin Wax to collect GSR, from then, it was popularly called
today as Paraffin test.
1914
Theodoro Gonzales performed a modified version of the Iturriuz Test using molten paraffin wax
on the hands of fire.
In 1933, he demonstrated the use of paraffin cast in the Criminal Identification Laboratory of Mexico, USA which was called the Dermal Nitrates Test, Diphenylamine Test and Gonzales Test.
1931
Paraffin test may also be positive if there is the presence of :
Fertilizer
Cosmetics
Urine
Tobacco
Positive result of Paraffin test.
Blue Color or Blue Specks
as stated by Edmond Locard, when two objects come into contact, exchange
of materials take place.
Locard’s Principle
Common Areas of Trace Evidence
- Hands – most common
- Face
- Clothing
- Objects Near the Place of incident
refers to the gunpowder residues that exits on all openings of a FA after discharge.
plumes
with the use of cotton with 5% Nitric Acid Solution, particles maybe collected.
Cotton Swabs
used for Scanning Electron Microscope (SEM) analysis.
Adhesive Stubs
Evaluation of Crime Scene (Relative to GSR)
- Time Factor is the most important consideration in dealing with GSR evidence.
- The standard Time Frame is 3-6 hours from the time of shooting BUT in some cases it may
persist much longer. - Careful preservation of clothing should be made.
- The Traditional belief to remove GSR on hands is by application of Vinegar.
Shapes of Trace Evidence
- They are generally spherical.
- Particles show overall cracking characteristics.
- Edges are straight or jagged to partially round.
NAA
Neutron Activation Analysis
ICP-MSP
= Inductively Coupled Plasma-Mass Spectroscopy Plasma – the most efficient method
employed in the analysis of GSR, computerized.
GFAAS
Graphite Furnace Atomic Absorption Spectroscopy – used in the analysis of inorganic
materials in primer residue such as Ba and Sb. .
detects the presence of nitrates and nitrites
Diphenylamine Test –
– detects presence of Lead Styhpnate (pb)
Sodium Rhodizonate Test
detects presence of nitrates in unburned or partially burned gunpowder, this is
also used by the investigator to detect the Range.
Walker Test
detects Nitrites
. Greiss test –
both detect nitrites, same with Greiss test
Marshall and Tiwari test
the chemical used to indicate the presence of nitrocellulose.
Lunge reagent
Unlawful Manufacture, Sale, Acquisition, Disposition or Possession of Explosives.
RA 8294, Sec 3
PENALTY ON VIOLATION OF RA 8294 SEC 3
Prision Mayor (Maximum) to Reclusion Temporal and a fine of 50,000.
normally employed as propellants for guns. Undergo deflagration from a few centimeters per second to approx 400M per second.
Low Explosives
also known as double-base powder. Undergo detonation from 914 to 9140 meters per second.
High Explosives
extremely sensitive to chemical shock, friction and heat such as Fulminate Mercury, Lead Styphnate & Lead Azide
Primary Explosive
insensitive to shock, friction and heat because there is a need to expose them to heat or flame to boost their power, like Dynamite (developed by Alfred Nobel), TNT, RDX, PETN and HMX.
Secondary Explosive
are also called blasting agents, such as Ammonium Nitrate/Fuel Oil Mixture.
Tertiary Explosives
