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Thread: How does the primer actually ignite?

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    How does the primer actually ignite?

    Will someone please tell me exactly what happens when the firing pin hits the primer? Does it cause a spark do to friction the lights the primer or what? Definitions just say "it's enough force to ignite the primer" but don't explain what actually happens between pin and primer.

    Thanks!

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    Quote Originally Posted by Zastavarian View Post
    Will someone please tell me exactly what happens when the firing pin hits the primer? Does it cause a spark do to friction the lights the primer or what? Definitions just say "it's enough force to ignite the primer" but don't explain what actually happens between pin and primer.

    Thanks!
    Without knowing specifics, I envision it working the same as do percussion caps in a toy capgun. The impact causes ignition, similar to how a diesel engine uses compression.

    Here is the "wiki-answers" explanation
    http://wiki.answers.com/Q/How_does_a_bullet_primer_work
    Last edited by wrightme; 01-12-2011 at 01:29 PM.
    "Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety." Benjamin Franklin

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    Quote Originally Posted by wrightme View Post
    Without knowing specifics, I envision it working the same as do percussion caps in a toy capgun. The impact causes ignition, similar to how a diesel engine uses compression.

    Here is the "wiki-answers" explanation
    http://wiki.answers.com/Q/How_does_a_bullet_primer_work
    Ah so it IS percussion! Thank you very much! I wonder why they use a pin and not just the hammer itself though?

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    Quote Originally Posted by Zastavarian View Post
    Ah so it IS percussion! Thank you very much! I wonder why they use a pin and not just the hammer itself though?
    Likely to concentrate the force. If the blow of the hammer face is sufficient, the hammer must be blocked from contact. Placing a firing pin in the middle would introduce a measure of safety.
    "Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety." Benjamin Franklin

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    Regular Member bigdaddy1's Avatar
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    How does the primer ignite????

    EXPLOSIVELY

    Sorry, couldnt resist.
    What part of "shall not be infringed" don't you understand?

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    Regular Member Nevada carrier's Avatar
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    The Handbook of Firearms and Ballistics, Second Edition, Written by Brian J. Heard has the following to say about primers.

    In rimfire ammunition, the firing pin crushes the soft hollow rim of the cartridge against the rear of the barrel to explode the priming compound.

    In centre fire ammunition, the priming compound is held in a cup in the base of the cartridge case. Merely striking the base of the cup with a firing pin would do little more than dislodge the priming compound from the cup. An anvil has to be provided for the priming compound to be crushed against by the impact of the firing pin. In modern ammunition, there are basically three ways in which this is achieved. These are called the Boxer, Berdan or battery cup priming system.

    The Berdan primer was designed in 1866 by Colonel Berdan of the US Army Ordnance Department. In this system, the anvil is actually part of the cartridge case in the form of a small peg in the primer pocket. Around the anvil are a number of small flash holes to permit the passage of the ignition flame from the primer to the propellant. Due to the ease and low cost of manufacture, Berdan primers are used mainly in military ammunition (Figure 2.4 ). The Boxer primer was developed in 1866 by Colonel Boxer of the Laboratory at the Royal Woolwich Arsenal, England. In this type of primer, the anvil is a small bent disc of steel which fits into the cup making the primer completely self - contained. The flash hole in the cartridge case is centrally located and as it is of a relatively large diameter (approximately 1.5 mm in pistol ammunition), it is thus quite easy to push out the fired cup with a thin rod for reloading purposes. Boxer - primed ammunition is almost exclusively used in commercial ammunition (Figure 2.5 ).

    The battery cup system consists of a plain cup with no anvil, which fits into a slightly larger inverted flanged cup containing its own anvil. The flanged cup provides a rigid support for the primer cup and anvil. This self - contained assembly fits into a recessed pocket in the base of the cartridge case. Battery cup primers are used exclusively in shotgun ammunition (Figure 2.6 ).
    Hope this helps
    Last edited by Nevada carrier; 01-12-2011 at 06:57 PM.

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    This definitely helps!

    My question was what makes the spark: Answer is "crushing the primer compound against an "anvil", er, hard metal surface". The rest I got. Thanks to all!

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    Quote Originally Posted by Zastavarian View Post
    This definitely helps!

    My question was what makes the spark: Answer is "crushing the primer compound against an "anvil", er, hard metal surface". The rest I got. Thanks to all!
    My guess is that the priming compound is sensitive to pressure. Being squeezed against the anvil is most likely sufficient to set it off. Don't underestimate the power of a Primer. If you were to reload a cartridge without a charge, the primer can produce sufficient energy to unseat the bullet. in Richard Lee's Modern Reloading, Second Edition, He discourages the use of tube fed primer feeders when reloading because there is a risk that setting off one primer will set them all off. The primer feed system on the Hornady AP press employs such a method. Richard Lee is likely Biased in his opinion considering that Hornady is one of his competitors.

    Richard Lee's Modern Reloading, Second Edition also has a section dedicated to primers, but I don't have that one in digital, only in print; I don't have the time to transcribe it. I'll summarize to say that it is less about how primers work, and more about the process of seating primers, and mistakes to look out for while doing so.
    Last edited by Nevada carrier; 01-12-2011 at 07:30 PM.

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    Regular Member Sc0tt's Avatar
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    Quote Originally Posted by Zastavarian View Post
    Will someone please tell me exactly what happens when the firing pin hits the primer?
    Auctually its magic!

    And your welcome.
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    Quote Originally Posted by Sc0tt View Post
    Auctually its magic!

    And your welcome.
    LOL LOL LOL

    I've always wondered this myself though, I guess Harry Potter points his wand at the gun and BANG.

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    Regular Member Nevada carrier's Avatar
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    Quote Originally Posted by XD40coyote View Post
    LOL LOL LOL

    I've always wondered this myself though, I guess Harry Potter points his wand at the gun and BANG.
    Actually, according to the Brady bunch, the lack of laws restricting guns causes them to go off.

  12. #12
    Regular Member SGB's Avatar
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    The material used in firearms primers for many years was potassium chlorate. In the early 1900's they used lead styphnate and after that diazodintrophenol.

    Not sure what is currently used.

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