Propellant type and combustion property (forensic ballistics)

1. Propellant type and combustion
property
ATULABHISHEK
M.Sc forensic science
Galgotias university, UP

2. PROPELLANTPROPELLANTPROPELLANTPROPELLANT
The propellant powder generates gas that propels the bullet
forward through the barrel & ejects the spent cartridge case.

3. Anatomy of a Bullet

4. Propellant powder/Charge
• Propellant charge may be categorized mainly as:
1. Black Powder
2. Smokeless powder2. Smokeless powder
3. Semi smokeless powder
4. Others

5. BLACK POWDERBLACK POWDERBLACK POWDERBLACK POWDER
• Black powder was the original gun powder and
the only known propellant and explosive until the
middle of the 10th century. It invented by Chinese
around the tenth century for giving signals and
fireworks.
• Composition:
Mixture of Saltpeter (Potassium nitrate-KNO3 or
sodium nitrate-NaNO3 ), Charcoal and sulfur with a
ratio (by weight) of approximately 75:15:10 respectively.

7. • Characteristics of black powder:
1. Not classified as high explosive because it has a very
slow decomposition rate and therefore a very low
brisance.
2. This same property that makes it a poor explosive,2. This same property that makes it a poor explosive,
make it useful as a propellant. (The lack of brisance
keeps the black powder from shattering a gun barrel,
and direct the energy to propelling the bullet).
3. When ignite it, produce a lot of smoke and some of the
powder is partly burnt or not burnt at all.

8. • Disadvantage:
1. Relatively low energy as compared to smokeless
powder.
2. Large quantity of shoot left behind.
3. Residue of burnt black powder in the barrel is
hygroscopic and an anhydrous caustic substance. When
moisture from the air is absorbed, potassium oxide ormoisture from the air is absorbed, potassium oxide or
sodium oxide turns into hydroxide, which will corrode
wrought iron or steel gun barrel.

9. SMOKELESS POWDERSMOKELESS POWDERSMOKELESS POWDERSMOKELESS POWDER
• It is categorized as:
1. Single Base Smokeless Powder
2. Double Base Smokeless Powder2. Double Base Smokeless Powder
3. Triple Base Smokeless Powder

10. Single Base Smokeless PowderSingle Base Smokeless PowderSingle Base Smokeless PowderSingle Base Smokeless Powder
In 1886, a French chemist Paul Vieille invented the first
smokeless powder, called Poudre B (Poudre Blanche =
white powder)
Poudre B was made from two forms of nitrocellulose
(collodion & gun cotton), softened with ethanol and ether(collodion & gun cotton), softened with ethanol and ether
and kneaded together. It was three times more powerful
than black powder.

11. Double Base Smokeless PowderDouble Base Smokeless PowderDouble Base Smokeless PowderDouble Base Smokeless Powder
To further increase the energy of smokeless
powder nitroglycerin can be added in amount up to
50%.
Double base powder burn faster than single baseDouble base powder burn faster than single base
powders.
Triple Base Smokeless PowderTriple Base Smokeless PowderTriple Base Smokeless PowderTriple Base Smokeless Powder
It consist of nitrocellulose, nitroglycerine and
nitro-guanidine

12. 1. Single Base Smokeless Powder
(nitrocellulose)
2. Double Base Smokeless Powder
(nitrocellulose 50% + nitroglycerin 50%)
3. Triple Base Smokeless Powder
(nitrocellulose + nitroglycerin + nitro guanidine)

13. SEMI SMOKELESS POWDER
Mixture of 80% of black powder and 20 % of smokeless
powder.
composition of the powder is as follows:
Nitrated wood cellulose 20%
Potassium nitrate 60%Potassium nitrate 60%
Carbon 12%
Sulphur 8%
This powder produces less smoke than gun powder but mixing
process is quite dangerous.
This aspect has prevented its extensive production and use.

14. OTHERS
1. Black Powder Substitute:
Hodgdon’s Pyrodex was the first widely available substitute
on the market.
Pyrodex is more powerful per unit of mass than blackPyrodex is more powerful per unit of mass than black
powder.
Pyrodex is similar in composition to black powder,
consisting primarily of charcoal, sulfur and potassium
nitrate but it also contains graphite and potassium
perchlorate and also sodium benzoate, dicyandiamide
along with small amount of dextrine and wax.

15. Disadvantage
With the increased safety of black powder substitute often
comes a reduced sensitivity to ignition.
2. Cordite
Cordite made by double based powder with mineral jelly.
-58% Nitroglycerine, 37% Nitrocellulose and 5% Mineral Jelly.
Modified Cordite -Modified Cordite -
DBP treated with alcohol (65% NC + 30% NG+ 5% Petroleum Jelly)
3. Ballistite
Ballistite has equal quantities of Nitroglycerin and Nitrocellulose without any
Mineral Jelly.
SBP treated with alcohol
- Developed and patented byAlfred Nobel
- His formulation (10% camphor + equal part of NG +
Collodion (NC solution in ether or alcohol)

16. Thank you !!Thank you !!