Safety risks of entirely eliminating pre-travel?

Discussion in 'Gunsmithing' started by creativetownsman, Dec 12, 2019.

  1. creativetownsman

    creativetownsman

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    Can any of you list reasons why eliminating pre-travel entirely might jeopardize safety with a Glock? I will define the foregoing elimination of pre-travel to mean that one will be at the resistance, or wall, from the get-go.

    It would be helpful if you would support each safety risk with an explanation of what parts, mechanisms would be effected and why they might be compromised.

    If anyone has an opinion that elimination of pre-travel would not affect safety or result in a dangerous condition, please state the reasons for such opinion.

    Thanks in advance to anyone who might contribute to this thread!

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    Last edited: Dec 12, 2019
  2. mtstream

    mtstream

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    The trigger safety can jam against the frame. If it happens it will make it very difficult to pull the trigger and/or the trigger safety will break.

    Glocks are mass produced guns - tolerances matter when it comes to reliability in Glocks. Playing with range/competition guns is fine as long as they remain safe. But removing tolerances from self defense guns is asking for a malfunction.
     
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  3. creativetownsman

    creativetownsman

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    Does it not also affect position of the cruciform on the drop safe shelves?



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  4. peng

    peng

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    How about that it simply would make the gun much easier to fire, thus less safe?

    Would you carry a 1911 cocked and unlocked?

    Not the same really, but pretty close. How about carrying a DA revolver with the hammer cocked? Why would you not do that?

    Eliminating the pre travel would eliminate the trigger safety right? That entire motion of ~ 1/2 inch pre travel is to allow the trigger bar to depress the plunger and allow the striker to access the firing pin.

    As mentioned also, from a manufacturing standpoint you would be ensuring that much of the production population would be scrap because you have a non symmetrical tolerance band.
     
  5. creativetownsman

    creativetownsman

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    Would you agree that reducing pre-travel can safely be done if it is less than entirely eliminated? I mean it's done all the time and would be safe so long as there is adequate clearance of the rear of the safety to the frame, correct?

    One of the major vendors provides a hex wrench that is also usable to determine minimum clearance of 0.035". Also, one can probably eyeball whether clearance is sufficient.


    View: https://youtu.be/UzFmUCzJrmg


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    Last edited: Dec 14, 2019
  6. peng

    peng

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    Yes they could probably reduce travel, but remember a clearance is not so much a dimension as it is a nominal and a tolerance band.

    If a gun has to function in all manufactured states, a bigger band means greater reliability and less scrap and warranty returns.
     
  7. fastbolt

    fastbolt

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    If you're looking for an informed opinion regarding the use of a Glock which has had the trigger pull specs modified for self defense, why not go over and ask Mas in the Gate Forum?

    Imagine your modified Glock being passed among jurors so they could feel what some DDA, or plaintiff's attorney in a civil case, might describe as a "hair trigger". Now, ask your attorney how much extra it's going to cost for your legal defense to bring in some "expert witnesses" to try and overcome any experts used by the prosecutor or plaintiff's counsel. How easy or hard do you want to make it for your attorney to keep you out of prison and/or bankruptcy?

    When you start fiddling with what's become de facto common 'Industry Specifications & Tolerances' for triggers for handguns created for use as dedicated service/duty weapons, you risk putting yourself outside the lines. If this were an older map, there might be the warning "Here be Dragons" in the borders.

    Go ask Mas ... and then ask your own attorney what he/she thinks of trying to defend you if for some reason the trigger pull/travel were to become an issue. Sometimes things can become a bit muddled beyond just calling someone's actions in some shooting incident "good" or "bad". Sometimes the Mens Rea (guilty mind) thing may come around to bite someone. You can't predict the circumstances you may encounter in any particular deadly force incident, but you can try to avoid setting yourself up for any unnecessary added liability and risks.
     
    Last edited: Dec 14, 2019
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  8. creativetownsman

    creativetownsman

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    I don't see how reducing pre-travel results in a hair trigger. I thought the pull itself remains the same weight. Am I mistaken?

    Will reducing pre-travel also result in the cruciform moving rearward along the shelves a bit?

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  9. mtstream

    mtstream

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    If we’re just talking self defense guns, then reducing the tolerances reduces the guns ability to function under a broad scope of situations. Less tolerance between the safety and the frame = More chance for debris to jam the movement. So a little pretravel and post travel on a Glock intended to defend your life is a good thing.

    To your question about the drop safety, it depends on how the Pre-travel is being removed. Fact is though, there is very little Pre-travel that actually can be removed. So my personal opinion is it’s an effort that doesn’t produce upside but can risk downside - especially for a self defense gun.
     
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  10. Bren

    Bren NRA Life Member

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    Because the "pretravel" is the process of pulling back the striker to full tension and having it not at full tension is one way Glock keeps it from firing if the striker lug slips off the sear due to an impact or something. Not just that, but depending on how you do it you may also be eliminating the drop safety and the trigger safety. Basically, a Glock that eliminated pretravel by setting an original style trigger and bar farther to the rear would be like carrying around a cocked revolver, only not quite as safe.
     
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  11. creativetownsman

    creativetownsman

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    Five questions here:

    Would the firing pin safety 'save the day' if due to an impact the sear falls off the lug?

    I'd like to know your views about that and with the trigger safety functioning and with it not functioning, the latter as more interesting from a safety standpoint.

    And, is the Glock standard trigger two-stage? If so, would eliminating all the pre-travel result in it becoming a single-stage trigger?

    Thanks for all the contributions thus far.
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    Last edited: Dec 14, 2019
  12. mtstream

    mtstream

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    Glock is a double action only trigger. This is how Glock has defined the gun for import (possibly other as well) purposes. Removing Pre-travel would not make it a single action.

    With an un-modified gun, yes, the firing pin safety would stop the firing pin if it were dropped and the contact between trigger and firing pin lug disconnected. The Glock armorers class used to teach testing the fining pin safety by pulling back the firing pin and letting go - but - they discovered repeating this damaged the safety so they don’t recommend it anymore.

    Disabling the trigger safety could result in the trigger being able to disengage the firing pin safety if dropped - the trigger spring pulls the trigger to the rear and it takes very little to contact and move the firing pin safety.

    For a Glock to be safe, all three safeties have to properly function.
     
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  13. creativetownsman

    creativetownsman

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    Is an AR-15 a double or single action firearm? I ask because one can get one stage or two stage triggers for it. And I thought a single stage trigger for that firearm did not have any slack or take up, whereas a two-stage trigger for that firearm did have slack or take up.

    Until now, I had thought that one and two stage triggers can be differentiated from single and double action firearms.

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  14. creativetownsman

    creativetownsman

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    On another matter, if the firearm sustains a fall from a hundred feet or so which safety is least likely to fail in a Glock?

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  15. mtstream

    mtstream

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    The term single stage vs two stage triggers is referring to rifle triggers.

    Pistols are referred to by their action.

    I have no idea what safety would fail at 100ft. All I know is that the safeties work at normal drop distances.
     
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  16. creativetownsman

    creativetownsman

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    Thanks for your clarifying post, above.

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  17. creativetownsman

    creativetownsman

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    I've 'discovered' an easy way to view interface of the vertical extension on the trigger bar with the FP plunger. Duh, never would have thought of this on my own, so I thank YouTuber 'Tactical Toolbox' for the idea that led me to the following:

    Place your unloaded pistol (with empty magazine well) into battery, turn the pistol upside down and shine a light up the mag well. One can see just how close the edge of the vertical extension is to the plunger, then slowly pull the trigger to the wall.

    At this stage, at the wall, it looks as if the plunger is depressed enough to release the firing pin, but it doesn't, at least on my pistol doing the shake test, which is reassuring.

    Anyway, I now can certainly appreciate how close (rear edge of the vertical extension actually in contact with the plunger) it is before even pulling the trigger. I can also view the interface with the trigger pulled half-way to the wall, which might simulate a reduction in pre-travel.
     
    Last edited: Dec 15, 2019
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  18. peng

    peng

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    Yes. Now try that exercise on 500,000 pistols and do the statistical math so you can begin to understand the tolerances necessary to maintain function under all conditions.

    Mass production design is not a nominal event but a statistical study of a population of data that will meet your requirements.

    What are you trying to achieve by reducing pre travel?

    There are plenty of other trigger feels and travels that might suit your needs better than a Glock.
     
  19. creativetownsman

    creativetownsman

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    I want to achieve faster, more accurate shots and it seems to be somewhat popular, so I figured why not? I feel it would be a more enjoyable shooting experience. However, I guess it would only apply to the first shot because I then shoot from the reset.

    But the first shot is the most important from a self-defense and a target shooting viewpoint.

    Moreover, the pistol is designed with greater tolerances than, for instance, a 1911. If you don't believe the Glock to be the AK of pistols then please explain to me why it is not.

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    Last edited: Dec 16, 2019
  20. creativetownsman

    creativetownsman

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    I can now answer my own question in the affirmative. Installed a new adjustable trigger shoe. With the trigger forward the cruciform is further back on the right drop safety shelf.
     
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