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  • The ammunitions construction.
    General construction.

    A cartridge is made of four pieces. The projectile, case, propellant and the primer.

    The projectile.
    The projectile is the piece of the cartridge that leaves the gun when fired. The earliest projectiles were made out of lead. They were easy and cheap to make. On the other hand they foul the barrels and had problems with gripping the rifling at a higher velocity, a thing that made the lead projectiles seldom went faster than 450 mps. To make the projectile better they made a jacket of metal around a lead core instead. Today, all military ammunition has a full metal jacket after a decision in the Haag conventions.

    The jacket may be made of either:
    Homogeneous Tombac (Tombac is an alloy between 90% copper and 10% zinc.)
    Tombac plated steel.
    Copper nickel platted steel. (Copper nickel is a alloy between 85% copper and 15% nickel)
    Copper nickel plated brass.
    The best jacket is made of Tombac. It can be made with very high precision and gives less wear in the barrel then for example copper nickel plated steel. The drawback is that Tombac is the most expensive of the materials here.

    The core is cold pressed and of led with ca 1-3% antimony. The antimony is to make the core harder.

    The only change from this is the 5,56x45 projectile that has a steel core in the front to give a better penetration on hard targets.
    9x19 m/39 6,5x55 5,56x45

    The case.
    The case has many functions. It encloses the propellant, holds the projectile and the primer. It should be formed so that it easily may be put in and pulled out of the chamber. At discharge of a cartridge, the case expands out of the heat and pressure. That means that the case seals of the chamber backwards so that gases don't leak out, and all the effect may move the projectile forward. After the firing the case shrinks back which means it is easy to extract from the chamber again. It is almost always out of brass in the military. During WW2 there where cases made out of brass plated steel too.
    8x57JS case

    The propellant.
    Gun powder is used as propellant in the cartridge. The powder burns quickly and creates a high pressure in the cartridge which pushes the projectile out of the barrel. The first kind of powder was the black powder. It was out dated in the early 1900 in favor of the smokeless powder, which had better performance and storage capabilities.

    The primer.
    The primer is what makes the powder to ignite. At a blow from the firing pin the primer bursts into flame and ignites the powder. The primer used in the Swedish military is almost always of the Berdan type. The exceptions I know about are the .38 special and the .50 BMG that is of the Boxer type. The difference between Berdan and Boxer is that the Boxer has an anvil mounted in the primer, while the Berdan have the anvil turned out in the cartridge. The biggest reason to use a Berdan is that it is cheaper to manufacture. 
    Berdan in 5,56x45 Boxer in .38 Special

    Copyright © 2000 Chris
    The Swedish military ammunition site