chapter 6 & 7 Flashcards
It is a small container or wafer of explosive material used to ignite the gunpowder.
The upper portion of the primer cup which is the complete assembly of priming composition, paper disk, anvil and vent.
Contains a highly sensitive mixture of chemical compound which when struck by the firing pin would detonate or ignite
PRIMER
Such reaction is called
PERCUSSION
Two Sizes and Types of Primers
1. Large Rifle .210 inches
2. Small Rifle .175 inches
3. Large Pistol .210 inches
4. Small Pistol .175 inches
Composition of Priming Mixture
1. Potassium Chlorate – 45 %
2. Antimony Sulfite – 23%
3. 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
is 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 very high rate that results to the propulsion of bullet.
Fuel (Antimony Sulfide)
in order to fire before, the gunpowder must have to be ignited
Igniting the Propellant
were the earliest firearms which use closed tubes, that needs manual ignition of its gunpowder.
Cannons
a small aperture drilled in the closed end of the tube, leading to the main powder charge. This hole was filled with finely ground powder, which was then ignited with a hot ember or torch.
Touchhole
External Priming
- Wheel-lock
- Flintlock
- Caplock
- Electric-fired
Internal Priming
- Rimfire – around the rim
- Pinfire – external pin is used in igniting the priming mixture
- Peripheral primer – combination of rim and pinfire, uses a pin that strikes a ring of a priming compound.
- Centerfire – primer is located at the center.
- Teat-fire – no rim. rounded at the rear, with a small “teat” that would protrude through a tiny opening in the rear of the cylinder.
- Electric-primed - Used by larger military gun and cannon rounds (such as the M50 20mm) utilize an internal electric primer that is activated by an externally-provided electric charge.
(powder charge, propellant, saltpeter, cordite, etc) The powder that is used in ammunition in the propulsion of projectile.
GUNPOWDER
Gunpowder in the ________ was known as -_________ - The ______________ until _________.
Considered the __________.
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.
- 19th century
- black powder
- First known chemical explosives
- 1800s
- oldest propellant
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)
– consists of jet black and shiny grains.
Composed of :
A. Potassium Nitrate – 75%
B. Charcoal – 15%
C. Sulfur – 10%
Black powder
– produces small amount of smoke.
Composed of:
A. Nitrocellulose – 60 parts
B. Nitroglycerine – 35 parts
C. Vaseline – 5 parts
Smokeless Powder
– 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 1st 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 firer. In 1933, he made a demonstrated the use of paraffin cast in Criminal Identification Laboratory of Mexico, USA which was called Dermal Nitrates Test, Diphenylamine Test and Gonzales Test.
1931
However, 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 swab
used for Scanning Electron Microscope (SEM) analysis.
Adhesive Stubs
Evaluation of Crime Scene (Relative to GSR)
1. Time Factor is the most important consideration in dealing with GSR evidence.
2. The standard Time Frame is 3-6 hours from the time of shooting BUT in some cases it may persist much longer.
3. Careful preservation of clothing should be made. 4. 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 is Prision Mayor (Maximum) to Reclusion Temporal and a fine of 50,000.
Penalty is Prision Mayor (Maximum) to Reclusion Temporal and a fine of 50,000.
are 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
