Bullet and Gunpowder

Bullet (of Rifle/revolver/pistol)

• Traditionally made of lead with antimony added for hardness, k/a round nose soft bullet.

Jacketed bullets are of 2 types:

1. Full metal jacket bullet
2. Semi jacketed bullet with nose fully or partly exposed 

Types of projectiles/bullet

• Lead shot: Present in shot gun cartridge, are of different sizes
• Jacketed conical bullets: fully or partially encased with copper or copper nickel, used in rifles.
• Hardened lead bullets: in pistol and revolver

Tracer bullet: 

• Leaves a visible mark in its flight
• Barium peroxide and magnesium are enclosed in base, give light as they pass.
• Incendiary bullet: contains phosphorus, burn the tissue.

Tandem bullet: 

• A pair of bullets are said to travel in tandem if the nose of one is in contact with the base of the other.
• This phenomenon is observed when the first bullet, having been stuck in the barrel, fails to leave the barrel, and is ejected by the subsequently fired bullet. 
• If the tandem bullets hit the target before separation, a single hole of entry is seen. 
• But if the bullets separate before they hit the target two entry holes on the same or on different targets may be observed.

Frangible bullets

• These bullets are designed to fragment upon impact. often to the point of disintegration. 
• Recovery and matching with a test bullet is difficult.

Souvenir bullets

• A bullet present for a long time in the body leading to dense fibrous tissue formation around it.
• Dum-dum bullet:Expanding bullet

• Is a jacketed bullet with its nose cut-off to expose the core.
•  It is designed to increase in diameter and expand upon striking the target
• Thus producing larger diameter wounds of limited penetration.

Ricochet bullet:

• It is a single bullet which strikes some intervening object first and then after ricocheting and rebounding strikes the target.

Yawning bullet: 

• A bullet travelling in an irregular fashion instead of straight line.

Gunpowder: 3 types

1.Black powder

• It is described in FG, FFG, FFFG and so on depending on the size of the grains.
• The finer and faster burning grains have more numbers of Fs.
• It contains PCS°
• Potassium nitrate (75%)°
• Charcoal (15%)°
• Sulphur (10°/0)°
• Only 44% of black powder is burnt into gas
• The powder grains are black, coarse or fine, burns with production of much heat, flame and smoke
• Fine grains travel 60-90 cm or more.

2. Smokeless powder 

• Smokeless gun powder is composed of nitrocellulose.
• Double based smokeless gunpowder consists of Nitrocellulose plus nitroglycerine.
• Nitrocellulose plus nitroglycerine plus nitroguanidine (triple base)
• 100% smokeless powder is burnt
• Produces much less smoke and are more completely burnt than black powder

Semi smokeless powder 

• Mix of 85% black and 15% smokeless powder 

Following things come out of a gun when fired

1. Projectile
2. Blast of highly compressed gases
3. Particle of unburnt /partly burnt powder
4. Smoke
5. Flame
6. Wads (in shotguns)
7. Fine lead fragments (in lead bullets )
8. Grease from the weapon
9. Empty cartridge