Gun Primer, How it works

 

Gun Primer, how it works

Hi guys! Thanks for tuning here into another blog.

A gun primer is a crucial component in ammunition, responsible for igniting the propellent that fires the projectile. It is a small, sensitive explosive device that, when struck by firing pin, generates a flame or hot gases to ignite the main propellent charge in a cartridge.

The below figure shows the cross section of  primer

Parts of a Gun Primer and Their Functions:

1.     Anvil:

·       Function: The anvil provides a hard surface against which the primer compound is crushed when the firing pin strikes the primer. This crushing action is necessary to initiate the primer compound’s explosive reaction

·       Details: In centerfire primers, the anvil is a small, often three-legged metal component inside the primer cup. In rimfire cartridges, the rim of the cartridges case acts as the anvil.

 

2.     Primer Cup:

·       Function: The primer cup holds the primer compound and the anvil. It forms the outer casing of the primer.

·       Details: Typically made of metal, the primer cup encloses the sensitive primer compound and protects it from accidental ignition. When struck by the firing pin, it deforms, pressing the primer compound against the anvil.

 

3.     Foil or seal:

·       Function: The foil or seal, sometimes called the foil disk, covers the primer compound and prevents contamination from moisture and other elements.

·       Details: It ensures the primer compound remains dry and stable, thus maintaining the reliability of the ignition.

 

4.     Flash Hole:

·       Function: The flash hole is a small opening in the cartridge case that allows the flame from the primer to reach the propellent inside the case.

·       Details: It is positioned at the base of the cartridge and is critical for ensuring consistent ignition of the propellent.

5.     Primer Compound:

·       Function: The primer compound is sensitive explosive material that ignites when crushed. It produces a flame or sparks to ignite the main propellent.

·       Details: Common primer compounds include lead styphnate, barium nitrate, antimony sulfide, and tetracene. These materials are chosen for their sensitivity, stability, and ability to generate a hot flame.

How a Gun Primer Works:

A.    Firing Pin Strike: When the firearms trigger is pulled, the firing pin moves forward and strikes the primer cup.

B.    Deformation: The impact deforms the primer cup, causing the primer compound inside to be crushed against to anvil.

C.    Ignition: The crushing action ignites the primer compound, generating a hot flame or gas.

D.    Flash Goes Through the Flash Holes: The main propellent charge ignites, creating rapidly expanding gases that propel the projectile down the barrel and out of the firearm.

The entire process happens almost instantaneously, allowing the projectile to be fired effectively. The reliability and sensitivity of the primer are critical for the proper functioning of ammunition.