trigger creep ??

Discussion in 'Technical Questions & Information' started by sidewayzlsx, Dec 6, 2009.

  1. sidewayzlsx

    sidewayzlsx New Member

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    Hello, Everybody! This is my first post on here and im relatively new to firearms. I keep hearing about trigger creep and I would like someone to explain to me what it means!
  2. carver

    carver Moderator

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    It simply means the distance the trigger will travel before the sear drops and the gun goes boom! Most trigger creep can be eliminated by a competant gun smith. A hair trigger is one that has had all creep removed and takes very little pressure to move the trigger and release the sear.
  3. Alpo

    Alpo Well-Known Member

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    Never heard the term, myself.

    Trigger's got three stages of movement.

    You got the first part, where the trigger is moving, but nothing else is happening. That's called "takeup", and sometimes "slop". Military rifles often have a lot of takeup. Double action automatics, when the hammer is cocked, usually have a lot of takeup. You can work with it, but the better triggers don't have any.

    Second part is the "travel". That's the distance the trigger moves, from when you first have tension on it until the hammer falls.

    Then you have "overtravel". That's the distance the trigger moves after the shot has been fired. Preferably, you don't want any overtravel. You want the trigger to break (that's what it's called when the hammer releases - the trigger "breaks") and then stop. Continuing to move can cause you to pull the gun off target. There are things called "trigger stops", that prevent overtravel.

    I've always heard that a "hair trigger" was one that had an extremely light pull. It was so light, that weight of a hair landing on it would set it off.
  4. Bindernut

    Bindernut Well-Known Member

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    Going by what Alpo posted (the "proper" terminology)...

    Creep would be what he defined as the travel portion of the trigger movement. The point after the initial take-up is gone, you've got tension on the trigger, and the trigger actually starts moving itself to disengage itself from the sear.

    A well tuned trigger should have a nice smooth "travel" that has a fairly even pull weight and no rough or gritty feel to it. It's also many times likened to feeling a glass rod break. Apply nice even pressure up to the point of that nice crisp snap.
    Usually it will be called creep on a "bad" trigger, one that is rough or has a lot of travel.

    The term hair trigger is like the term creep...Not a textbook definition, but pretty common when some folks talk guns. I would call a hair trigger one that has both a very light pull weight and also very little travel.

    Some trigger designs have more travel than others and can't safely be tuned up to reduce the travel distance...the key is not so much the amount of travel but rmostly to have it smooth and even throughout that stage.
    Last edited: Dec 6, 2009
  5. LDBennett

    LDBennett Well-Known Member

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    The sear engagement in a simple hammer and sear trigger system is a narrow notch usually on the hammer. The sear is held into that notch which measures in the 10 of thousandths of an inch, by the sear spring with the engagement angles such that the sear tends to stay engaged. A correct trigger has those angles such that the hammer must move ever so slightly farther to the rear to release. No matter what happens before or after, the motion of the trigger to move the sear off that hammer notch is commonly termed creep. All trigger systems must have enough creep (sear engagement in the hammer) to assure the gun is safe. Trigger jobs minimize the creep but can not or should not eliminate it as the gun would be totally unsafe if the creep was zero. A small amount of creep is not normally felt by the shooter.

    As to what is pre-travel and what is creep, in the technical sense only the motion of the trigger to move the sear out of engagement when the sear drags across the hammer notch is "travel" or creep. The motion before the sear starts to move is pre-travel and the motion after the hammer falls is over-travel. Good single stage triggers minimize these two phases of the trigger pull.

    Two stage triggers usually have lots of creep but with a low force level and a silky smooth feel required to move the trigger to the break point. Close to that break point in the trigger travel, an additional force is added, which is easily felt, to get the hammer to fall. Some of these two stage trigger have spring loaded protrusion that provide the extra force. Some, mostly military triggers, change the leverage ratio when the sear is about to break to get the extra force so you can recognize the break point is near.

    I have seen trigger systems where the sear engagement surfaces are so highly polished or even chrome plated such that the creep was long but the action during that phase so smooth as to make you believe the trigger had no creep at all. The problem with that is that the break point is almost random to the feel of the trigger pull and such a trigger is exceedingly smooth but hard to control.

    LDBennett
    Last edited: Dec 7, 2009
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