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1911 hammer falls to saftey notch when trigger is pulled

Discussion in 'Handguns: Autoloaders' started by RSVP2RIP, Feb 17, 2011.


    RSVP2RIP Well-Known Member

    I have a Colt Mk IV (series 80) 1911 that the hammer catches on the half cock when the trigger is pulled very gently. When it is pulled in a more hurried jerk it doesn't catch on the notch and goes all the way down. I did replace the saftey a few months ago and never noticed this condition until doing a little dry firing today. Before you ask, no, it does not have a trigger stop. I have not changed any internals other than the grip saftey and the manual saftey, the sear, hammer, trigger, disconector are all stock. What the hell is going on?

    Edit: The trigger does have a minimum to nonexistant amount of overtravel as-is.
  2. Sniper X

    Sniper X Well-Known Member

    I had a similar problem when a buddy who bought my Kimm Tac Cus II took it apart to take off the magwell/housing. When he put it back together he didn't get the leaf spring back in right and weird things were happening when he pulled the triger. But mostly it would allow the hammer to fall when you racked the slide. Maybe you have a similar problem. How about a total disassemble reassemble to see if that cures it?
  3. Quack

    Quack Well-Known Member

    that is where i would suspect the problem is. you most likely need to file some material off the lower notch to get a little more rearward travel of the trigger bow. it can either be that the arm that blocks the trigger needs some more clearance when the GS is pressed, so that the trigger bow can pass under it. The area that might be causing the problem is parallel to the trigger bow need some more clearance to provide more rearward travel.

  4. Control

    Control Well-Known Member

    First, check your leaf spring install as was already suggested.

    Next, does the problem get worse when the grip safety is not fully pressed in? Does it go away completly if you leave the grip safety out? If so, you might have a case where the trigger bar is rubbing the grip safety when it should not.

    [Quack was typing at the same time I was!....]

    RSVP2RIP Well-Known Member

    I think you might have it. When I put it on I was kinda puzzled that it "worked" without having to fit that. I must have never noticed it before or something is starting to wear in and causing it to be an issue now. I'll give it a go and a since it will be taken down that far already, the leaf spring will be reinstalled.
  6. Quack

    Quack Well-Known Member

    the other things that i can think of is that the trigger bow is a little longer than the old trigger, so there is not enough pre-travel/take-up. have you tried the old trigger?

    If the trigger bow is not oversized, then the sear feet might need some fitting as well to get the proper take-up/pre-travel.

    try this test...

    Make sure the gun is empty and no ammo around
    pull the trigger so that the hammer is fully down.
    keep holding the trigger and then pull the slide back just far enough so that the hammer is at 1/2 cock.
    ease the slide into battery.
    release the trigger.
    the trigger should reset. if not, then you may not have enough pre-travel.

    NVM...mis-read the original post. i thought that you replaced the trigger and sear.
    Last edited: Feb 17, 2011

    RSVP2RIP Well-Known Member

    Did it anyways and it does reset. I tried filing down the bottom tab as far as I felt comfortable with and slimmed the bottom of the upper tab and that did not help. I did not take out the sear or hammer yet to look at those. Could it be that the sear has a burr on it?
  8. BullfrogKen

    BullfrogKen Moderator Emeritus

    Put the original parts back in and check to see if it still occurs.

    I wager the thumb safety you installed isn't within spec. I've seen that problem occur before. Sometimes the stud on the thumb safety can be peened. Most often parts are simply replaced with ones of known quality.
  9. 1911Tuner

    1911Tuner Moderator Emeritus

    Assuming that the trigger doesn't have an overtravel screw that has moved and is preventing full rearward trigger travel...look to the disconnect. It's falling out of position and slipping off the sear. It could be due to insufficient spade/sear foot overlap, or it could be due to a weak or damaged center leg of the sear spring. Also possible that the center leg of the spring is placed too high on the angled portion of the disconnect...but not highly likely if the spring is OEM.

    Since you changed the grip safety, there's also a small possibility that the built-in overtravel stop is mislocated, and keeping the trigger from full travel. Best place to start is to put the original Gs back in the gun and see if the problem resolves itself. If it does, you have your answer. If not...look at the sear spring and disconnect.
  10. RSVP2RIP

    RSVP2RIP Well-Known Member

    The same problem repeats itself with the stock grip saftey. The sear spring is about halfway up the angled part of the disconector, but the spring is very stiff still. The foot overlaps half the spade when the trigger is depressed.Observing through the back of the frame when pulling the trigger, it seems like everything is where it is supposed to be/doing what it should. On a whim I put a stock spur hammer in with the stock grip saftey and I could not get the condition to repeat itself. So does this mean I have a hammer out of spec? I feel leary about stoning the half cock notch as I feel this is one of the most important saftey items on the 1911, but is there a simnple fix if this is the problem or just get a new hammer?

    Looking at the hammer there is a definite bur that has developed on the half cock notch leading edge.
  11. Quack

    Quack Well-Known Member

    what hammer are you using?
  12. RSVP2RIP

    RSVP2RIP Well-Known Member

    Stock commander style came with the gun and has the half cock issue, and I dropped in a stock spur hammer (also Colt) and didn't have any issues.

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