Firearm propellant

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Cordite is a type of firearm propellant using shaped pieces rather than a powder form.

Firearm propellants are a specialized type of

barrel of a firearm. Mixtures of different chemical substances are often used to control the rate of gas release, or prevent decomposition of the propellant prior to use. The pressure relationships between propellant chemical reactions and bullet response are described as internal ballistics
.

History

The oldest gun propellant was

solid propellant (mostly for antique firearms and pyrotechnics). Modern firearm propellants however are smokeless powders based on nitrocellulose or similarly nitrated organic compounds,[1] first invented in the late 19th century as a cleaner and better-performing replacement for black powder. Modern smokeless powder may be corned into small spherical balls, or extruded into cylinders or strips with many cross-sectional shapes using solvents such as ether
, which can be cut into short ("flakes") or long pieces ("cords").

Mechanism

When a propellant is ignited and begins to

exothermic nature of the reaction. These combustion gases become highly pressurized in a confined space – such as a cartridge casing. This rapid pressurization and expansion of gas forces the projectile (the bullet, shot (pellet), or slug) down the gun barrel, imparting high kinetic energy from the propellant gases and accelerating the projectile to its muzzle velocity. The projectile motion driven by the propellant inside the gun is known as the internal ballistics.[2]

Due to the relatively short distance a gun barrel can offer, the

byproducts (e.g. unburnt powders, dislodged foulings
).

Characteristics

The performance characteristics of a propellant are greatly influenced by its grain size and shape, because the specific surface area influences the burn rate, which in turn influences the rate of pressurization. Short-barrel firearms such as handguns necessitate faster-burning propellants to obtain sufficient muzzle energy, while long guns typically use slower-burning propellants. Propellants are typically manufactured in grains of geometric shapes to physically control rate of gas production in accordance with Piobert's law.[3] Shotgun and handgun propellants may be flakes, while Improved Military Rifle propellants were extruded as short cylindrical tubes, and ball propellants are small spheres.[4]

Types of propellant

References

  1. ISBN 0913022-00-4
    .
  2. ^ Smith, Selwyn D. (1965). Interior Ballistics of Guns. Washington DC: United States Army Material Command. pp. 1–2.
  3. ISBN 978-0854041275
    .
  4. ISBN 0-935632-10-7
    .
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