2022 Scientific Officer Ballistic (JKPSC) Part 1 (Q1 to Q25)

Answer: (2) Colt assault weapon system

Explanation: Some references also stated that CAWS stands for Close Assault Weapon System.

Answer: (3) Spheroid shape

Explanation: The classic three-component Pb–Ba–Sb spheroid particle in GSR should be
described as being characteristic of GSR rather than unique to GSR.

Answer: (2) Repeater type 

Explanation:
-> Repeater Type Shotgun: Designed for magazine loading.
-> Multiple Shells: Holds several shells in the magazine.
-> Automatic Loading: After firing, the shotgun automatically loads the next shell from the magazine into the chamber.
-> Quick Successive Shots: Allows for faster shooting compared to single-shot or double-barrel shotguns.

Answer: (3) Powder glass particles if used, will abrade the barrel resulting in the increase of bore diameter

Explanation: Mercury fulminate primer suffers from five major drawbacks:
-> Mercury Release: Mercury fulminate releases mercury on ignition.
-> Brittle Brass Cases: It makes the brass cases brittle and consequently unfit for frequent use.
-> Barrel Deterioration: Barrels get deteriorated quickly because of the deposition of mercury on their surface.
-> Potassium Chlorate Issue: Potassium chlorate when ignited produces potassium chloride, which absorbs moisture resulting on early rusting of barrels.
-> Abrasive Powder Glass: If powder glass particles are used, they can abrade the barrel, increasing its bore diameter.

Answer: (4) Stock

Explanation: Stock is a wood, metal, or plastic frame that holds the barrel and action and allows the gun to be held firmly.

Answer: (1) 6-8%

Explanation: In India, the new primer composition being used is:
-> Lead Styphnate: 32.42%
-> Antimony Sulphide: 13.17%
-> Barium nitrate: 27- 37%
-> PETN: 4 – 6%
-> Tetracene: 3-5%
-> Aluminum: 6-8%
Reference: Content from BHU study materials.

Answer: (3) Section 3 of the Arms Act, 1959

Explanation: The following are the major sections of the Arms Act, of 1959.
-> Section 1: Short title, extent, and commencement of the Act.
-> Section 2: Definitions of terms used in the Act.
-> Section 3: Requirement for a license to possess or carry firearms and ammunition.
-> Section 4: Not directly mentioned, but generally follows with specific regulations or exemptions.
-> Section 5: Authority to make rules regarding the Act.
Reference: The Arms Act 1959 by Indiacode.nic.in

Answer: (1) Barium peroxide and Magnesium powder

Explanation: Common tracer compositions:
-> German Tracer Composition (World War I): magnesium, strontium nitrate, calcium hydroxide, and rosin
-> Americal Tracer compositions:

• World War I: Barium peroxide and Magnesium in grain alcohol.
• Post-World War I: Barium nitrate, Barium peroxide, and Magnesium loaded in hollow brass bullet with an igniter mixture of barium peroxide and magnesium.

-> American Tracer Bullet (1926 onwards): High-pressure mixture of Aluminum, Potassium perchlorate, and High-density calomel (to increase brilliance and luminosity of the trace).
-> Tracer Rounds (Caliber .50 and .45): Red, green, and white signal rounds.
Reference: Engineering Design Handbook, Military Pyrotechnics Series By United States. Army Materiel Command.

Answer: (3) Sodium Rhodizanate test

Explanation:
-> Sodium Rhodizanate Test:

• Reagents: Sodium Rhodizonate, 0.1N Hydrochloric Acid (HCl), ammonia solution.
• For Lead: Purple coloration.
• For Barium: Red/brown coloration after ammonia treatment.

-> Walker’s Test:

• Reagent: Photographic paper, hypo fixer, 5% 2-naphthylamine-4,8-disulphonic acid, 20% Acetic Acid.
• For Nitrites: Bright red spot.

-> Greiss Test:

• Reagents: Naphthylamine instead of 2-naphthylamine-4,8-disulphonic acid.
• For Nitrites: Orange spots.

Answer: (4) 9.14mm

Explanation: Check the diameters of various shots: Lead Shots Sizes: Gauge, Bore, Diameter, and Weight

Answer: (1) Zip guns

Explanation:
-> Carbine is a type of rifle with a shorter barrel than a standard rifle.
-> LMG (Light Machine Gun) is used by a single infantryman with or without an assistant and is majorly used by military and special forces.
-> Derringers is a single-shot pistol usually of large caliber, typically .41 or .44. They are small pocket firearms having multiple barrels, each of which is loaded and fired separately. The traditional derringer has two barrels.

Answer: (2) Peppering

Explanation:
-> Tattooing is caused by the embedding of unburn or semi-burn powder particles (also called peppering or stippling).
-> Blackening is due to the deposition of soot or unburnt residue, causing a blackening effect that can be removed using a cotton swab.
-> Charring: burning or carbonization of the skin.
-> Wipe ring: sometimes called dirt ring, describes the mark left on the target or surface where a bullet has wiped off lubricant, dirt, or metal as it passed through.

Answer: (3) 10% HCL

Explanation:
-> The GSR is swabbed with a piece of cotton cloth, and moistened with HCl (10%) or with nitric acid (5%).
-> 10% Acetone and 10% Ethanol are organic solvents that could remove oils and other organic substances not primarily used for metals.
-> 10% Sulphuric acid is a very strong acid and can be corrosive.

Answer: (3) Contact shot

Explanation: Read More: Determine the Range of Firing From Wounds

Answer: (1) Mercury fulminate

Explanation:
-> Mercury fulminate is a primary explosive and highly sensitive to heat, shock, or friction and is used to initiate the detonation of a charge.
-> Nitro Glycerin is a high explosive and is mostly used (in excess) in the manufacture of dynamite and other explosive compounds.
-> Ballistite is a double-base smokeless propellant made from a combination of nitrocellulose and nitroglycerin.
-> Cordite, a smokeless powder that is a mixture of nitrocellulose, nitroglycerine, and petroleum jelly.

Answer: (4) Tamancha

Explanation:
-> Tamancha is a locally made handgun, often with a single-shot capacity and requiring manual extraction of the spent cartridge.
-> All other firearms on the list have ejector marks.

Answer: (3) 1.85

Explanation: Check the diameters of various shots: Lead Shots Sizes: Gauge, Bore, Diameter, and Weight (in the table the diameter is given in inches and mm, you can convert mm into cm by multiplying 10.)

Answer: (2) Kevlar

Explanation: Some commonly used fabrics in ballistics:
-> Kevlar was the first commercialized aromatic polyamide (para-aramid) fiber by DuPont in the early 1960s.
-> Twaron is another para-aramid fiber developed by Akzo Nobel (now Teijin Twaron), popularly used in modern ballistic body armor.
-> Ultra-high molecular weight polyethylene (UHMWPE) is a high-performance fiber used for ballistic protection.

Answer: (1) 40-50m/sec.

Explanation:
-> Threshold Velocity for Skin Penetration: About 40-50 meters per second
-> Threshold Velocity for Bone Penetration: 60 meters per second.
-> Factors Influencing Wounding Effect:

• Target Site: For example, a head injury will be different from a wound on the waist.
• Velocity of the Projectile: Speed of the projectile at the moment of impact significantly affects the severity and nature of the wound.
• Constructional Features: Design and materials of the projectile influence its wounding capability.
• Range of Firing: The proximity of the shooter to the target affects the wound, with contact injuries differing markedly from those caused by shots fired from a distance.

Reference: Content from BHU study materials.

Answer: (2) 5 years

Explanation: For cartridge SA 12 bore 70mm plastic ASTRAM, if properly stored in packed condition, the expected shelf life is around 5 years.
Reference: Equipment Catgalogue by Federation of Indian Chambers of Commerce & Industry.

Answer: (2) Dermal nitrate test

Explanation:
-> Dermal nitrate test: It required the application of hot paraffin or wax to the suspect’s hand with a paintbrush.
-> After drying into a solid crust, the paraffin was removed and tested with diphenylamine.
-> Indication: A blue color indicated a positive reaction for nitrates.
-> Problem with specificity: The test has fallen into disfavor with law enforcement agencies, owing mainly to its lack of specificity.
-> False Positive Test: fertilizers, cosmetics, urine, and tobacco all give positive reactions.

-> Phenolphthalein Test: to detect the presence of blood based on the peroxidase activity of hemoglobin.
-> Benzidine Test: historically used as a chemical test for the presence of blood.

Answer: (4) Black gunpowder

Explanation:
-> Fineness of Powder Grains= fineness of grains (F)/size of grain (G)
-> Based on the extent of fitness and grain size, the black powder fineness can be defined in terms of FG, FFG, FFFG.
-> Small firearms usually use FFG or FFFG as a priming charge. While FG is mainly employed in cannons and large-bore shotguns.

Answer: (4) The complete assembly of cartridge case, primer, propellant and projectile that is to be fired in a gun

Explanation: The complete assembly of the cartridge case, primer, propellant, and projectile that is to be fired in a gun is termed as live ammunition.

Answer: (3) SEM used in conjunction with EDAX

Explanation:
-> SEM (Scanning Electron Microscopy) used in conjunction with EDAX (Energy Dispersive X-ray Analysis) is used to analyze for the presence of Gunshot Residue (GSR).
-> This allows for the detailed examination of the microscopic particles that compose GSR, identifying their shape and elemental composition.

-> Polarized Light Microscopy and Microspectrophotometry are majorly used for various types of analyses such as fiber and paint analysis.
-> Refractive Index Measurements are primarily used in the examination of glass fragments.

Answer: (2) The pattern of minute parallel striations that make up the mark made by a particular rifling land on bullet(s) recovered from the scene

Explanation: Minute parallel striations are unique to the firearm’s barrel that fired the bullet, acting like a fingerprint for the gun.