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Bump on Trigger Bar

  1. I'd be interested in opinions on the bump on the trigger bar used to mechanically center it under the firing-pin stop. My new Glock 26 Gen 4 clearly has this prominent bump. This YouTube argues that while this works to keeps it centered, it's at the expense of friction and significantly increased trigger pull. Curious if people polish this down?

    Any update from anyone? Found this related reference here: https://www.glocktalk.com/threads/bump-on-the-trigger-bar-of-g23-g4.1625036/#post-23260949

  2. The trigger bar with the bump is on the Gen 4 in case the person wants to reverse the mag catch.

    If you don't like the feel then put a Gen 3 trigger bar in the pistol. Just don't change the mag catch if you do that.
  3. Is that supposed to be a joke? There is absolutely no relationship of trigger bar to magazine catch, reversed or otherwise, in any generation of Glock pistol. There is nothing true in the quote above.
    NOTE from 07/17/16: What I wrote above is incorrect, as I acknowledge in post #12. My apologies to domino1.

    The bump on the trigger bar's firing pin safety arm is there for only one reason...ensure proper alignment of the arm under the firing pin safety.

    This bump has been on the trigger bars of all generations of every Glock pistol ever made in 10mm, .45ACP, and .45GAP. That goes back to 1990...26 years!! You can not buy an OEM trigger bar for such pistols without the bump. (OK...you can buy one for .45GAP Glocks because they use the trigger bars for the smaller caliber Glocks for which bumpless versions are available.) That terrible bump never caused any great outcry or protest about trigger pull from owners of those pistols.

    But when it showed up in 2010 on all other calibers of Gen4 pistols as a product improvement, some acted like it was some novel and alien and harmful degradation. Presumably those folks were totally unaware that by 2010 the bump had been around on all larger caliber Glocks for 15 years without notable complaint.

    I have put Gen4 trigger bars in all-OEM Gen3 pistols, and put Gen3 trigger bars in all-OEM Gen4 pistols, cycling through all four Glock OEM connectors, and I have never measured an increase in trigger pull beyond 0.2-lbf...usually it was less. Very insignificant. Since the bump prevents misalignment of the trigger bar's FP safety arm which could potentially cause the FP to impact the primer with less than full spring force, it serves a very useful purpose and has no significant disadvantage. I use a Gen4 trigger with trigger bar in all my pre-Gen4 Glocks that I use for EDC...where functional reliability has a high priority.

    All-OEM Gen4 pistols have a 0.5-lbf higher trigger pull for a specific connector installation, compared to all-OEM pre-Gen4 pistols. That's because the connector in the Gen4 trigger mechanism housing and frame is very slightly CCW (viewed from right side) to the same installation in a pre-Gen4 TMH and frame. This connector mounting difference causes the heavier pull. The bump on the trigger bar does not.
  4. Actually, domino1 is exactly right concerning the purpose of the bump in the smaller than .45acp guns. The bump was implemented on the non-.45 acp/10mm guns to correct an occasional malfunction that happens during a round firing when the magazine catch is reversed. If the mag catch is not reversed it is not necessary. This was discussed in the Advanced Armorer Course.

    This is not the reason, as Mike-M points out, that it has existed on the larger caliber guns since the beginning. On those calibers, the bump does exist to center the vertical extension on the firing pin safety. And Mike's exactly right about the bump was not causing the increased trigger weight in the early Gen4s (like many old you-tube videos claim) it was due to a change in the trigger housing and corrected with the release of the dot connector.
  5. Another person, here, that knows that bump doesn't cause any significant pull weight, difference. If your trigger bar is bent in the wrong direction, it can press the bump into the slide, more, and cause some resistance, but if your trigger bar is not bent, that bump barely touches the slide during the trigger pull. A few strokes on the tip of the bump and where it rides against the slide (about half an inch) with 1500 wet dry and a tiny dab of heat resistant grease, there, and you can be sure it isn't making your pull weight any greater. If the FPS plunger and the area of the trigger bar that enables it are less than smooth, that would cause more resistance than the bump does. Some people say removing the bump helped their trigger pull, but I've done a number of Glock trigger polishes and just didn't notice much when it came to polishing the bump and the area of the slide where it rides. I did get peace of mind that those areas are smooth, now, and aren't causing any issues. It's highly probable that it never was.
  6. It was explained in armorers school that if the mag catch is reversed the pressure from the catch is transferred to the magazine which can press on the magazine body which can press on the trigger bar which can possibly result in the misalignment and subsequent depression of the firing pin safety plunger. Sorry about the run-on sentence. The bump is supposed to make sure that the tab is centered under the plunger, to reliably deactivate the firing pin safety when the trigger is pulled.
  7. Have you actually shot the pistol yet? That often helps.
  8. Thanks for the clarification.
  9. All I can say is, GOOD INFO AND THANKS.
  10. Sorry, I got back to this late but the others clarified it well. Thanks mtstream and Cpl Jerry Lewis!

  11. For 9/40 trigger bars....

    Gen 3.....

    Gen 4....

  12. I've been off the forum for a day and a half, and when I returned to this thread I see several posts like #4, #5, and #6 that contain good explanatory information. The most important is the justification of the alignment bump on the trigger bar's firing pin safety arm for Gen4 pistols in calibers below 10mm and .45, based on the Gen4 pistol permitting the magazine catch to be installed on the right side of the frame.

    I have inspected my Gen4 and pre-Gen4 pistols and I find those explanations to be wholly reasonable with demonstrable basis. I will attempt to summarize this information below, because I have never read anything similar on any Glock forum since the Gen4 models were released in 2010:

    1. The normal installation of the Glock magazine catch on the left side of the frame in all generations of Glock pistols causes the magazine catch to pull the front top of the magazine towards the left within the clearances of the magazine well. This moves the right side of the magazine top away from the trigger bar, which prevents all interaction of the magazine with the trigger bar.

    2. The optional installation of the Glock magazine catch on the right side of the frame in Gen4 Glock pistols causes the magazine catch to pull the front top of the magazine towards the right within the clearances of the magazine well. This moves the right side of the magazine top into close proximity to the trigger bar, where it can rub against and push the trigger bar to the right while the trigger bar moves backward as the trigger is pulled. This could cause the trigger bar's firing pin safety arm under the firing pin safety to misalign too far to the right, resulting in lack of sufficient elevation of the firing pin safety in the slide. In that event, free travel of the firing pin through the firing pin safety would fail at time of fire. The alignment bump on the right side of the firing pin safety arm on Gen4 trigger bars ensures that its right-directed misalignment is limited.

    Most of the effects described in item 2 above can be easily observed after the slide is removed. Insert a magazine and twist it to the right, just as the right-side magazine catch does. Then move the trigger bar to the rear while watching for small right-side movement of its firing pin safety arm. It's pretty hard to characterize this undesirable and unexpected interaction of the magazine tube with the trigger bar when the magazine catch is on the right as "Glock Perfection". In fact, the engineering here is just a little disappointing...that bump seems like an ersatz solution. :)

    Through it all, one statement remains universal: The bump ensures proper alignment of the trigger bar's firing pin safety arm under the FP safety...regardless of pistol model. I will continue to use Gen4 trigger bars in my pre-Gen4 pistols (1) because I have found no degradation of trigger pull arising from such use, and (2) because I have always found the off-to-the-right-side travel of the FP safety arm under the FP safety on all models to be a source of minor concern as the FP safety wears with use.

    There's one other issue that comes out of this: It has long been a popular cure-all for those who hate the Gen4 bump in small caliber Glocks to replace the Gen4 Trigger with Trigger Bar with the Gen3 equivalent. Without any doubt, some of those Gen3 bumpless TwTBs now reside in Gen4 pistols that have their magazine catch installed on the right-hand side. This is now clearly a demonstrably defective configuration, especially if the pistol is intended for serious weapons use in which functional reliability is essential.

    I have found this thread to be rewarding and instructive to me. Thanks to those who have contributed. I apologize to domino1 for failure to understand the basis for the point he made in post #2.
  13. Well, Mike - I guess you found out that "there are no absolutes"!

    Wait a second... I just stated an absolute, didn't I? :supergrin:
  14. Well written Mike. In the advanced course Scotty went into some related information that even after asking lots of questions I still cant completely wrap my head around - related to counter balance of the trigger bar under the pressures of live fire. I wish I could give more but at best I would be regurgitating information I can't explain or defend and the net net is still the same - the bump is only necessary on the smaller calibers when the catch is reversed.

    I'll never understand why Glock doesn't try to make information like this or like the change in the G42/43 connector easily accessible. I do have to give them credit for allowing civilians to take their courses though. Wish others did the same.
  15. There is no need to be long-winded. Just admit you were wrong, and a jerk about it.
  16. Perhaps then you and I can form a club. You obviously qualify for leader, and I for the intelligent one who speaks English. :)
  17. :alex:
  18. When you apologize for being a jerk, and wrong in the same post, I'll let you in my club.

    Hundreds of words, then apologizing for "misunderstanding" something you essentially regurgitated back, at the very end, is not very grown-up of you.

    You were a jerk, and wrong. Apologize for that.

    My club's for grown-ups.
  19. Is the above supposed to be a joke? No apology for being a jerk?

    Being wrong is fine. Everybody's wrong more than they'd like to admit.

    It's the obnoxious way you chose to try to belittle someone, that begs for apology.
  20. Probably isn't necessary to get involved, here, but I see TWO correction of errors WITHOUT content removal before t4 started driving in the nails. Guess we should tar and feather, too. Lordy...........
  21. Personally, I trust the factory engineers and gun designers more, MUCH MORE, than some person with enough time on his hands to make these amateurish videos.

    Don't polish or grind off bumps intentionally put there by Glock as part of the design of the pistol.
  22. I notice these threads on the 'bump' get smaller and smaller. Maybe those are figuring out the bump really isn't a big deal. I'm very critical. If it was making a difference, I would say it. FWIW.
  23. It makes a small difference...I guess the question is: is it enough to matter?
  24. I use 1000, 1200, and 1500 grit wet dry paper, depending on how rough the surface is, to do my trigger polishes. I finish, of course, with compound and glaze, to get that 'brilliant' shine. I never even messed with the bump until that was done on prolly 5 or 6 of my Glocks, and that was due to reading my first 'bump' thread, here. Pull weights, after I polished everything, with all out of the box parts, averaged 4lbs, 10 to 12 ozs, before I polished the bumps in those guns (these Glocks came with 4.5 connectors and are Gen 4's). The pull weights stayed the same. Not only that, when I put grease on the slide where that bump rides, the bump literally was barely touching the slide. The grease trail was minute. I would like to reverse a mag catch on one and do a 'lefty' to see what the pull weights are. I have no idea 'cause I've never shot a 'lefty' Glock. My guess, just by looking at everything, is it can be tuned to also barely touch the slide while it does what it is designed to do.
  25. As I tried to illustrate earlier, it's not an issue of the bump rubbing the slide and causing friction, but it causing the rear of the trigger bar...the 'blade'...to push in more on the connector (which has a slight outward angle), via leverage. In the second video you can see how the bar moves slightly outwards at the end of the pull/trigger break with the Gen 3 bar, but not with the Gen 4. So I don't think it's a pull weight thing as much as it is a little stiffer feel before break.
  26. I have used both Gen 3 and 4 bars on the same G4 pistol many times. The Gen 3 trigger bar results in a smoother trigger. After thousands and thousands of rounds, no negative affect has been noticed by switching a Gen 3 bar into a G4 frame.
  27. I get that. I don't believe the bump is pushing the trigger bar over. Matter of fact, I know it doesn't. That resistance you're speaking of has to do with the angle of the connector.
  28. Now Now You Kids Play Nice!! :cheers::cowboy::fred:
  29. Well, the actual thing is, I know it is, and I've witnessed and repeated it on my own between a Gen 3 and 4 bar in the same gun. You can see the movement in one and not the other. And when compared side-by-side, there is no angle of difference between Gen 3 and 4 trigger housings and connectors...much like in the first video. So it's clearly the bump, but not in the way that many may think.

    It's not so much 'pushing the trigger bar over', as it is keeping it from pushing out with the connector's outward angle. It's small, but it is there. Not trying to be argumentative, but it is indeed a fact that it's there...and I had to really compare to be sure. Again, some may notice it...and care...more than others. And if not, all the better...one less thing to concern oneself about.
  30. :popcorn:
  31. I did too...I, unknowingly, got a gen 3 smooth-faced trigger and bar to replace the serrated-face one in my gen 4 g26. I immediately noticed a little difference (not huge) which I would describe as a little less stacking/hitching as it approached the break. Later realized that I had a gen 3 bar in. Tried the original gen 4 bar in a gen 3 G19 and it felt a bit stiffer like the G26 did at first. Interestingly, the sideways movement of the trigger bar that I mentioned earlier is more noticeable on the G19 than the G26, end coincidentally so it the felt difference in trigger pull. Neither with the gen 4 bar was unshootable or unpleasant. Frankly if i didn't have them side to side for comparison, I'd be fine with the gen 4's.....especially for carry.
  32. Gravedigging a thread instead of starting a new one. I understand why the bump was added to all Gen 4 pistols.

    What I don’t understand is why the bump was necessary on all Large Frame pistols and GAP pistols. I know the Firing Pin Safety on these is larger. I assume the bump was required to keep the TWTB mechanically centered with the FPS. Why?

    An ancillary question, what would happen if one used a ‘bumpless’ TWTB (part #357) in a G37. More specifically a G37 NOT intended for use as a serious weapon, but only for fun and games.