Forensic Ballistics

December 06, 2020 BY Taniya Jaiswal

Forensic Ballistics Quiz Crafted by-

Mr. Manish Kumar Saini

Scientific Officer (Physics)

State Forensic Science Laboratory,

Madhya Pradesh

About the quiz creator

Master of Science (Forensic Science) from Bundelkhand University, Jhansi in 2007

Qualified UGC-NET

Practiced as a ‘Private Handwriting and Fingerprints Expert’ in District Courts of Uttarakhand and U.P. till October, 2009.

Worked as ‘Research Associate’ in Ballistics Division, Central Forensic Science Laboratory, Chandigarh from October, 2009 to March, 2012.

Carried out Ph.D Course work in 2013 from Punjabi University, Patiala

Worked as Senior Scientific Assistant (Ballistics) in Forensic Science Laboratory, GNCT of Delhi from December, 2013 to May, 2015.

Got selected through MPPSC in State Forensic Science Laboratory, Madiya Pradesh for the post of Scientific Officer (Physics), (Rs 15600-39100 + Grade pay 5400/-), Home (Police) Department and posted at Ballistics Division, SFSL, Sagar in May, 2015. Reported more than 500 cases during the tenure in Ballistics Division.

In July 2020, transferred to Voice Analysis Lab, Regional Forensic Science Laboratory, Bhopal.

Introduction to Forensic Ballistics

Forensic ballistics involves the examination of evidence from firearms that may have been used in a crime. When a bullet is fired from a gun, the gun leaves microscopic marks on the bullet and cartridge case. These marks are like ballistic fingerprints. If investigators recover bullets from a crime scene, forensic examiners can test-fire a suspect’s gun, then compare the marks on the crime scene bullet to marks on the test-fired bullet. The examiner will then assess how similar the two sets of marks are and determine if the bullets are likely to have been fired from the same gun or different guns. Cartridge cases are compared in the same way.

In forensic science, the study of ballistics is the study of motion, dynamics, angular movement, and effects of projectile units (bullets, missiles, and bombs). There are many applications of ballistics within a criminal investigation.

Bullets that are fired at the scene of a crime will be examined in the hopes of discovering several pieces of information. The actual bullets can identify what type of gun the criminal used and whether or not the firearm is connected to any other crime. The amount of damage a bullet has sustained upon hitting a hard surface can help determine approximately where the shooter was standing, what angle the gun was fired from, and when the gun was fired. Any residue on the bullet can be studied and compared to residue on the hand of a suspect, the gun that was fired, or any object that was close by when the firearm was used. This information helps researchers uncover the identity of the shooter. When the bullets are missing, the type of impact they made can still lead investigators to ascertain what kind of bullet the criminal used, and therefore the type of gun as well.

Here is the List of Questions with Answers along with explanation

Ques 1. Annulus position of a centre fire communication is-

(a) Neck portion of cartridge case to crimp bullet

(b) Lead filling portion of bullet

(d) Space between cartridge head and body

Answer –(c) Space between the primer cup and primer pocket

Explanation – A centerfire cartridge is a firearm metallic cartridge whose primer is located at the center of the base of its casing (i.e. “case head”). Unlike rimfire cartridges, the centerfire primer is typically a separate component seated into a recessed cavity (known as the primer pocket) in the case head, and is replaceable by reloading.

Ques 2. In Rebated cartridge case-

(a) Rim diameter is equal to the diameter of cartridge case

(b) Rim diameter is less than the diameter of cartridge case

(d) Cartridge case having a flanged head larger than body

Answer – (b) Rim diameter is less than the diameter of cartridge case

Explanation – Rebated rim cartridges have a rim that is significantly smaller in diameter than the base of the case, serving only for extraction. ... One example of a rebated rim cartridge is the . 50 Action Express (or . 50 AE), commonly chambered in the Desert Eagle pistol.

Ques 3. Chronograph is the device to measure-

(a) Chamber pressure of firearm

(b) Velocity of missiles

(d) Impact of bullet on target

Answer – (b) Velocity of missiles

Explanation – Chronograph, an instrument which can be used to measure elapsed time in terms of split seconds, seconds, or minutes. In addition, some chronographs indicate day, month, year, and phases of the moon on separate dials or openings which are superimposed on the face of the timepiece.

Ballistic chronographs are used to measure the velocity of projectiles bullets. This is important to help in developing formulas for different gunpowders and designing bullet shapes and gun components.

Ques 4. Escutcheon is a small metal plate on a weapon displaying

(a) Proof mark of country

(b) Company name

(d) Caliber of a weapon

Answer - (b) Company name

Explanation – Heraldry is the practice of devising, granting, displaying, describing, and recording coats of arms and heraldic badges. In heraldry, an escutcheon, or scutcheon, is the shield displayed in a coat of arms. The escutcheon shape is based on the Medieval shields that were used by knights in combat. The shape varied from region to region and over time.

The shield is used in heraldry not only for men but corporate bodies: city corporations, universities and schools, companies, churches and for various official offices.

Ques 5. Gilding metal is a alloy use is bullet jackets have composition-

(a) Copper 90-95%, Tin 5-10%

(b) Copper 90-95%, Zinc 5-10

(d) Copper 90-95%, aluminum 5-10%

Answer – (b) Copper 90-95%, Zinc 5-10

Explanation - Gilding metal is a form of brass (an alloy of copper and zinc) with a much higher copper content than zinc content. Exact figures range from 95% copper and 5% zinc. Gilding metal is used for various purposes, including the jackets of bullets, driving bands on some artillery shells, as well as enameled badges and other jewelry. The sheet is widely used for craft metalworking by hammer working. It is also used particularly as a lower-cost training material for silversmiths

Ques 6. Pyrodex is modern substitute of-

(a) Primer

(b) Black powder

(d) Blank powder

Answer - (b) Black powder

Explanation - Pyrodex, and most other black powder substitutes, are formulated to be a volume-for-volume equivalent of black powder, not an equivalent mass-for-mass (weight-for-weight). Pyrodex is measured by volumetric measurement techniques, not in grains on a scale, due to the difference in density of Pyrodex versus black powder.

Hodgdon's Pyrodex was the first widely available substitute on the market. Pyrodex is less sensitive to ignition than black powder, and uses the same shipping and storage guidelines as smokeless powder. Pyrodex is more energetic per unit of mass than black powder, but it is less dense, and can be substituted at a 1:1 ratio by volume for black powder in many applications. Pyrodex is similar in composition to black powder, consisting primarily of charcoal, sulfur, and potassium nitrate, but it also contains graphite and potassium perchlorate.

Ques 7. Ratchet is –

(q) Notched area at the rear of the cylinder of a revolver.

(b) Notched area at the front of the cylinder of a revolver.

(d) Inside portion at the body of the cylinder of revolver.

Answer –(a) Notched area at the rear of the cylinder of a revolver.

Explanation – Ratchet A notched area at the rear of the cylinder of a revolver which causes the cylinder to rotate when moved by the hand. The most common method of rotating the cylinder is a ratchet mechanism. ..Double action revolvers are keyed to the trigger so that as the trigger is pulled, a ratchet arm pushes the cylinder so that it rotates and positions the next occupied chamber for firing.

Ques 8. Nutation is a unstable condition of bullet due to –

(a) Rotational effect of bullet about mid axis.

(b) Progressive corkscrew motion of the bullet.

(d) Earth’s gravitational pull

Answer –(b) Progressive corkscrew motion of the bullet.

Explanation –Nutation. This is the progressive corkscrew motion of the bullet. This action is very similar to the wobble observed immediately after a top or gyroscope is initially set spinning and is a function of the spin rate being too great.

Ques 9. In pistol ammunition, the diameter of boxer primer cup is-

(a) 1.2mm

(b) 1.5mm

(d) 5.1mm

Answer –(b) 1.5mm

Explanation - The Boxer primer was developed in 1866 by Colonel Boxer of the Laboratory at the Royal Woolwich Arsenal, England. In this type of primer, the anvil is a small bent disc of steel which fits into the cup making the primer completely self-contained. The flash hole in the cartridge case is centrally located and as it is of a relatively large diameter (approximately 1.5 mm in pistol ammunition), it is thus quite easy to push out the fired cup with a thin rod for reloading purposes. Boxer-primed ammunition is almost exclusively used in commercial ammunition.

Ques 10. Which one of the following used as oxidizer in primer-

(a) Strontium nitrate.

(b) Zinc sulfide.

(d) Antimony sulfide

Answer – (a) Strontium nitrate.

Explanation - Strontium nitrate is an inorganic compound composed of the elements strontium, nitrogen and oxygen with the formula Sr(NO3)2. This colorless solid is used as a red colorant and oxidizer in pyrotechnics. Primer composition comprising diazodinitrophenol or potassium dinitrobenzofuroxane, tetracene, nitrate ester fuel and strontium nitrate. It is prepared by hydrating anhydrous strontium nitrate by dissolving in warm water and thereafter cooling solution to obtain crystals of the tetrahydrate. These crystals are mixed with other components to form the primer composition.

Ques 11. Name of Australian ballistic identification system is -

(a) ARSENAL

(b) TAIS

(d) FIREBALL

Answer – (d) FIREBALL

Explanation – The firearm identification system called Fireball was developed by Edith Cowan University in 1995, and it has been used by Australia Police Services for identifying, storing, and retrieving the images of projectiles and cartridge cases. The major limitation of Fire-ball is that the shape and position are tuned manually and thus the precision of comparisons relies on the expertise and experience of the end-user.

Ques12. Powder tattooing can also be turned as -

(a) Scorching

(b) Charring

(d) singeing

Answer –(c) Stippling

Explanation – The tattooing is also known as peppering or stippling. It is the deposit of unburnt or semi-burnt powder particles under the skin. Tattooing, normally, cannot be removed with a wash. Tattooing is an ante- mortem phenomenon and shows that the individual was alive at the time he was shot. If the individual was lifeless before being shot, even though the powder may produce marks on the skin, these marks have a moist gray or yellow appearance rather than the reddish brown to orange-red coloration of an ante- mortem injury. There should be no difficulty with differentiating the two.

Ques 13. The barrel of a carbine is usually not more than-

(a) 20 inches

(b) 21 inches

(d) 15 inches

Answer - (c) 22 inches

Explanation - A carbine is a long-barreled firearm with a shorter barrel than a standard rifle or musket. Most carbines are shortened versions of full-length rifles, shooting the same type of ammunition, while others fire generally lower-powered ammunition, including types designed for pistols.

Ques 14. Ricochet means-

(a) Tampered bullet

(b) Unfired bullet

(d) Misfire bullet

Answer - (c) Deflection of the bullet

Explanation - When a bullet strikes a target of sufficient solidarity at low angle it may, while maintaining its integrity, be deflected from its original path as a result of impact and travel in a direction quite different from its original one. Such a deflection of a bullet constitutes a true ricochet.

Ques 15. Distance travel by the firearm discharge in chronological order is-

(a) Burning, Charring, Blackening and Powder Tattooing.

(b) Charring, Blackening, Burning and Powder Tattooing.

(d) Powder Tattooing, Charring, Blackening and Burning.

Answer – (a) Burning, Charring, Blackening and Powder Tattooing.

Explanation - Charring/ Scorching/ Burning/ Singeing

These are the effects of flame or hot gases produced in the combustion of propellants. The charring is caused when the shot is fired from a very close range.

Blackening

The blackening is caused by the smoke deposits. The smoke particles are light. They do not travel afar. Therefore, smoke deposit i.e. blackening is limited to a short range. The colour of smoke is grey to black in black powder and light grey to dark grey in smokeless powder.

Tattooing

The tattooing is also known as peppering or stippling. It is the deposit of unburnt or semi-burnt powder particles under the skin. Tattooing, normally, cannot be removed with a wash.

Forensic Ballistics

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