extractor

Discussion in 'Technical Questions & Information' started by colt, Aug 8, 2009.

  1. colt

    colt New Member

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    I just started taking gunsmithing classes on line just to build my knowledge of guns. Lots for me learn. Exactly when does the cartridge engage in the extractor? Would it be engaged before you pull the trigger or does the recoil after you fire send it back into it? May be a lame question, but have to learn exactly whats going on and when. Much Thanks.
  2. Alpo

    Alpo Well-Known Member

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    In every gun I can think of that has one, the extractor is holding on to the cartridge when it is in the chamber. On many guns the extractor engages long before the cartridge is fully seated.

    If it did not engage the cartridge before it was fired, how would you be able to remove the cartridge without firing it?

    Are you possibly getting the extractor confused with the ejector?

    When the bolt is closed and a round is chambered, the extractor (which is usually a hook shaped thingy attached to the bolt or slide) is stuck in the extractor groove of the cartridge case. When the bolt moves backwards the hook pulls the cartridge case out of the chamber. When the bolt gets far enough back the ejector kicks it off the extractor hook and out the ejection port. The ejector can be either just a piece of steel that the moving bolt/slide pulls the cartridge back onto, or it can be a spring-loaded plunger that, when the bolt/slide gets to a certain spot, trips the spring and the plunger comes forward and kicks the cartridge out.
  3. colt

    colt New Member

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    Thanks Al, thats what I was thinking, but had to be sure. Thanks,
  4. LDBennett

    LDBennett Well-Known Member

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    The exception is blowback operated rimfire guns.

    Most have an extractor whose job is to hold the cartridge case against the bolt face while the case itself pushes the bolt open. It holds the case on the bolt so the ejector can reach it and throw the empty case out of the gun. The extractor basically controls the direction the empties will be sent.

    In addition, there is a ramped surface in the breech face of the barrel that pushes the extractor out of engagement when the cartridge is fully seated in the chamber. When the cartridge is fired it pushes the bolt and itself rearward and the extractor snaps back over the rim to control the empty case for ejection. I suspect this feature is there to allow the chamber to be shaped to get the most amount of the case supported by the chamber.

    The secondary job of the extractor is to aid in the removal of an unfired cartridge. In normal operation (gun firing) the extractor is not really necessary except to aim the ejected case out of the chamber area. In fact some blowback operated rimfire guns don't have a extractor at all. An example is the Beretta break open rimfire semi-autos where the break open feature allows an unfired cartridge to be removed from the barrel.

    LDBennett
    Last edited: Aug 8, 2009
  5. colt

    colt New Member

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    Lots of good info LD. Thanks for the reply.
  6. Hammerslagger

    Hammerslagger New Member

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    LDBennet and Alpo wrote excellent answers.

    I will expand on LDB's answer by noting that the center-fire Beretta .32 "Tomcat" has no extractor, either.

    Beretta relies on the residual pressure of "blow-back" operation to extract (blow) the fired case from the chamber in both their .22 RF and .32 ACP sub compact (pocket) pistols.

    This feature leaves one in a desperate situation in the event of encountering a dead primer in a life or death confrontation, as there is no extractor to extract the "dud" round by "racking' the action. Therefore, I must eliminate such designs for personal defense.

    I will expand on extractor design and function by noting that magazine fed firearms come in two common designs or "flavors"; "control feed' and "push feed".

    A control feed system is designed to pick up the round from the magazine and put (slide) the rim or annular grooved part of the cartridge (usually called "rim", even in rimless designs) between the hook of the extractor and the breech (bolt) face before inserting (shoving) it into the chamber.

    The push feed design shoves the cartridge into the chamber and pushes the extractor (or extractors) over the rear of the cartridge into the desired position for extraction, as the bolt is locking.

    Some controlled feed designs have extractors that are designed so that they can be forced over the rear of a chambered cartridge. The US Model 1911 pistol and the US Model 1903 rifle being two well known examples. However, this practice often quickly damages and/or breaks these leaf spring type extractors and should be avoided. Some more modern pivoting dual design extractors are more durable; but I still opine that it is better practice to always chamber a round from the magazine of a "controlled feed" design firearm


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  7. LDBennett

    LDBennett Well-Known Member

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    It should be remembered that when we are talking about a rimfire gun the end of the barrel has a cam faced cut that engages the extractor and pushes it off the rim when the cartridge is full seated.

    If it is push feed then the extractor may never snap over the rim in seating the cartridge in the chamber whereas if it is control feed (as all the rimfire guns are that I have seen.....but I have not in any way seen them all) the rim of the case goes up and under the extractor as the bolt is closing only to be pushed off the rim when the cartridge becomes fully seated by the cut in the barrel operating on the extractor face. When the gun is fired the rimfire case acts as a piston and pushes the bolt back (the barrel is fixed to the frame and is stationary) and the extractor then engages the rim of the case after the rim does its initial unseating of itself from the chamber. The extractor, in normal firing of the gun, only holds the rim of the fired case securely against the bolt face and acts as a hinge for the ejector and guides the fired case out of the gun. It only "extracts" for unloading the chamber manually.

    So the answer depends on the cartridge and the gun it turns out.

    LDBennett
    Last edited: Aug 13, 2009
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