Glock Pre-travel Adjustment

[Garrett]

I was looking at the pre-travel adjustment modification on http://limitedgun1.bei.t-online.de/reset.html and started wondering, how do you check to see if the drop safety is still working properly after making the mod? You can hold the slide upside down next to the frame and see about where things match up, but you really need the slide installed on the frame to be sure. So how do you make sure your drop safety is still functional?

[racine]

I'm just as curious but mainly on the Front Sight article that showed some drilling and installation of a screw to achieve the same effect. My question is I am having trouble visualizing the mods on the trigger safety itself. Can anyone share some photos on what exactly is done? Thanks in advance.

Racine

[vincent]

I would not recommend this modification and I'm suprised that Front Sight published the details. It's going to lead to a lot of home 'smiths creating unsafe Glocks. Reducing pre-travel can easily disable both the firing pin block safety and the drop safety (that's two out of three)!! If you want to put a set screw in, put it in the back of the trigger housing window to reduce over-travel (vs. pre-travel). The pre-travel only affects the first shot. Reducing the overtravel and therefore the reset distance is a much more valuable modification for a competition gun.

Similar topic

http://glocktalk.com/showthread.php?s=&threadid=175820

[racine]

Good point Vincent! I do think some shooters would opt for this for rapid fire modes. Have you read the article? I think the writer does clarify that none of the safeties are disabled or did I misread it. Thanks for your valuable input nevertheless...

Racine

[vincent]

I have read the article and handled guns with this modification. I've also heard people say that no safeties were disabled. Some know what they are talking about, some don't. The reason I'm speaking up is that it is easy to get into trouble with this particular modification and the gain is minimal. If you don't know the action enough to understand how ALL the safeties work and how to check the various engagements then this is not a something to try.

Maybe someone else has a different opinion.

-Vincent

[Flexmoney]

Reducing pre-travel can easily disable both the firing pin block safety and the drop safety (that's two out of three)!

I'll add that all THREE safties may be disabled. If the forward travel of the trigger is stopped, it might also (likely) mean that the trigger safety won't engage either.

[the duck of death]

I looked over these mods and decided there not for me. I shoot the same Glock 23 I carry in IDPA/SSP USPSA/PRODUCTION. Never have had a problem with trigger take up and I release the trigger all the way not just to reset.

I worked on the trigger & have a smooth 2.8lb pull. That's about as far as I'm willing to go w/ a Glock.

Oh, and no malfunctions or failure to fire in over 10K rounds.

[Garrett]

Since nobody was willing/able to answer the question, I figured it out for myself. I had epoxied a small spacer in the front of the... part. (firing pin mounting block?) It got rid of most of the take-up, and felt really good. However, as Flex pointed out, the trigger safety was now disengaged. I still did not know about the firing pin safety though. Here's how it's supposed to work: When the trigger is pulled back, a bump on the trigger bar pushes up a plunger in the slide that moves the block out of the way of the striker. If the trigger is pre-set too far back, the striker may be un-blocked with the trigger not being pulled.

So how do you check for this?

You need to see if the striker will move forward when the trigger is not being pulled. I removed the back plate from the slide and pulled the striker out. I removed the striker spring and re-installed the striker. I then installed the slide on the frame. With the back plate off, I should be able to push the striker forward until it either protrudes from the breechface, or is stopped by the firing pin safety. In my case, the safety was still working and stopped the striker. This leads me to think that if the trigger is not set back far enough to disengage the trigger safety, the firing pin safety should still be working properly.

I took a small file to the shim that I had installed to pre-set the trigger and started cutting it back. Now, my trigger moves forward just enough to reset the trigger safety. This may seem like a neat mod the first time you pull the trigger, but it doesn't really help much. The pre-travel won't be there after the first shot anyway. I think an overtravel adjustment would be much more benificial. I think I'll try the set screw on this one though. It would be much more adjustable, and more easily reversable.

[Fireglock]

To check the drop safety pull the slide. With the trigger in it's forward position press down on the top of the trigger bar where it forms the crucible, if it moves down at all you have disabled the drop safety. The modification you have performed will most likely disable that safety. Additionally if you look up through the magwell with a small flashlight you can see if the firing pin safety is being touched by the trigger bar. It works and is a lot less time consuming than taking your slide apart.

[Garrett]

To check the drop safety pull the slide. With the trigger in it's forward position press down on the top of the trigger bar where it forms the crucible, if it moves down at all you have disabled the drop safety. The modification you have performed will most likely disable that safety. Additionally if you look up through the magwell with a small flashlight you can see if the firing pin safety is being touched by the trigger bar. It works and is a lot less time consuming than taking your slide apart.

Sure, now you tell me

[eric nielsen]

Bump for an great post by Fireglock. It's quite relevant now because of the many threads on this forum & others regarding the Glockworx Fulcrum trigger and pretravel, firing-pin-block safety function and so on. BTW all the links in this thread are now dead which is just as well: if you want pre and post travel adjustment in a normal [non-Fulcrum] trigger you are better off buying the fully adjustable ejector housing from Vanek.

Like the first poster I was setting the upper next to the lower to try to eyeball the FPB safety's alignment with the trigger-bar push-tab. Looking at the complete gun through the magwell to have a look will show you many interesting things. Watch the slide come back home and see if the FPB stays clear of the trigger, watch the trigger work the FPB as you pull the trigger, etc.

I had NO IDEA how off-center my Vanek's push-tab was pressing on the FPB plunger. I had swapped out the rounded Vanek plunger for the factory one just get a better "tink" sound after putting the overtravel of my gun the way I liked it [which does help, let me dial out more overtravel.] I plan to use a hammer & vice to change the push-tab angle, using some OEM trigger first as "practice". Unlike the ejector , there is plenty of room to move the point of the push-tab and cycle the slide, but rounds going into the chamber might start to touch it - something to watch for.

Be aware that no 2 combinations of parts are going to engage/release the inner-trigger, the FPB plunger, or the drop-safety notch the same way - at all. After racking the slide with the trigger held back, my full-out Vanek will get a connector "click", then release the FPB, then just a couple millimeters later it releases the trigger-safety. One of my OEM triggers [with repositioned spring hole] will release the FPB and then years & years later it finally releases the trigger safety. I imagine the reverse could also happen: trigger safety pops out but FPB isn't released. Please LOOK.

An easier way to check the drop-safety function is to just remove the slide, push out the rear pin & pull up your ejector housing a little and look at how the trigger sits in the plastic notch. If it's up near the top of the ramp, you're dancing on the edge of too little over-travel JUST from the safety aspect. That same setting may not push up the FPB plunger enough either, inviting misfires.

It's possible to go criminally-negligent and get an almost 1911-type travel that shoots, and releases it's trigger-safety, but there is NO WAY the firing-pin-block is functioning in that state. I don't have a Glockworx trigger and their FPs and connectors are currently "out" for redesign but it would be good for ChronoMan to be trained to take a flashlite and confirm safety as there are many new triggers out there.

If you know what you're doing, it's possible to get a very short overall trigger action on a glock that still respects all 3 safeties. Depending on parts, even similar to the travel of a CZ or Tanfo single-action gun - and safe. With that setup you may find that you like the reset and feedback of the factory striker spring [much] better than the reduced 4lb springs. Hitting the primers harder is just a bonus.

[the duck of death]

Here's how I limit pre travel:

liminating trigger take up:

Make sure the Glock is unloaded

1. Remove the slide from the frame.

2. Move the trigger forward so that the right wing of the cruciform sear (facing forward) is slightly on the right hand portion of the drop safety.

4. Drill a tiny hole in the ejector housing in front of the left drop safety arm of the cruciform sear.

5. Counter sink the hole so the slide doesn't rub on the pin.

6. Insert the pin and put the slide on and cock the striker.

7. Pull the trigger safety away from the trigger and mark it where it meets the frame( this is in back of the trigger).

8. Re slot the trigger safety at the mark.

Take up will be minimized and all 3 safeties will work.

[eric nielsen]

What you just wrote is fine if the FP-block plunger gets released. Also I didn't want to get into it but re-doing the back of the safety trigger is fine [and all else being equal, safe] for LTD and Open but not legal in Production. I also make the face of my safety-triggers flush with the main trigger - again safe but not legal in Production.

Better/more responsible would be to use the magwell/flashlite check to see where the FPB is released [so it's blocking the striker] and mark that point on the side of your trigger-guard directly under the tip of the trigger. Then do whatever pinning you like. Personally I see an internal pin as being a failure-prone item that wasn't there originally. You can buy the Vanek ejector housing for 35 bucks. Or you could heat & bend the spring tab forward to limit pretravel.

All three pretravel methods [my opinion] need to be checked for [3] functioning safeties. Get 2 of 3 working with the FPB not releasing and now you have a gun that you and the RO assume is safe in the holster - but if dropped - can easily fire.

[the duck of death]

Some pre travel must be left or the firing pin safety and the right hand side of the drop safety WILL be defeated.

Has there been a ruling that re cutting the trigger safety is not allowed in Prod? It is not a visible exterior mod.

There are several ways to limit take up, I like the pin in the ejector housing.

Edited January 21, 2010 by the duck of death

[Nik Habicht]

Some pre travel must be left or the firing pin safety and the right hand side of the drop safety WILL be defeated.

Has there been a ruling that re cutting the trigger safety is not allowed in Prod? It is not a visible exterior mod.

There are several ways to limit take up, I like the pin in the ejector housing.

The Production rules changed half-way through 2009. Unless you can find specific language authorizing the modification, it's not legal....

[the duck of death]

*QUOTE*

For purposes of this clause, a “trigger

safety” is externally visible, and must

remain operable.

All I could find, what am I missing?

[Nik Habicht]

*QUOTE*

For purposes of this clause, a “trigger

safety” is externally visible, and must

remain operable.

All I could find, what am I missing?

Duck,

you're missing language that allows you to modify the trigger safety.....

Read the first page of the interpretation very carefully -- if it's not listed as an approved modification, it's not legal. If anyone alleges that you're shooting an illegally modified blaster, the burden of proof rests on the you to demonstrate that all modifications are in fact permitted....

First page for easy reference:

NROI Interpretation for the Production Division Equipment Rules (Appendix D4)

June 25, 2009

General interpretation(s):

In accordance with the direction of the Board and their statement of intent with regard to Production Division equipment rules, NROI hereby issues the following

ruling:

External modifications continue to be strictly constrained to items specifically listed below.

Some specific classes of internal modifications are now specifically allowed, but in general internal modifications remain constrained to items specifically listed.

If a conflict appears to exist between these general statements and the listed details, below, the specifics listed in the notes and clarifications below shall be deemed definitive.

The burden of responsibility is on the shooter to ensure that his/her equipment is compliant with these provisions. If a modification is disputed – either by a Match Official or a competitor, under 11.1.2 and 11.7 – the competitor may be required to provide evidence of a specific clause in the rules or published NROI rulings which specifically authorizes the modification.

While the rules are currently silent on a Match Official’s authority to disassemble a competitor’s equipment, a competitor may – at any time – be required to prove that the equipment is compliant with the equipment rules, up to and including the disassembly of their equipment to verify compliance and proper function (e.g., the proper operation of factory safety mechanisms).

A competitor who cannot demonstrate that his/her equipment is compliant with these provisions will be moved to Open Division, under 6.2.5.1

Except as specifically modified below, all other clauses in Appendix D4 remain in effect, along with any applicable NROI rulings. In order to carry binding authority

in competition, an NROI ruling must be published in Front Sight and/or on the USPSA web-page.

Does that help?

[eric nielsen]

If you file or cut on the back of the black plastic safety trigger, it will be visible as a slightly different color or texture. If you ask 10 random people at a match to look over a glock & spot production-legal issues, I guarantee someone will spot it quickly.

Just like the hole that's left after repositioning a trigger pivot pin. It's on the outside - hand people your gun and they will notice right away. Okay for Ltd, L10, and Open - that's it.

After finding this thread I hit on the magic Google phrase which is "pretravel glock" - no dashes - and expand out the GT hits. Even with all that discussion and the adventures in Glockworx spamming, there were only a couple references to using a flashlight and watching the FPB movement. There was a great post on that by Yar, a person very late onto the Glockworx team if I understand correctly.

To re-phrase a little bit: there is a wide variance in the dimensions of the trigger parts just by Glock alone, before talking aftermarket. Multiple vendors for the trigger bar and connector. If you get one with a long nose, it releases the striker further forward as if you put a "long" trigger in a 1911. If you get one with a shorter nose, it releases much further back, better for people with short fingers. Moving the trigger pivot pin can move the release point and it can change how much the FPB is depressed too. All of this is a great reason to check the function of all 3 safeties after you change parts or adjust overtravel and especially pretravel.

Also, way back when, Glock figured out EXACTLY what angles to put on their 3 connector types and EXACTLY what curve on the trigger nose will work with all 3. They made sure these work in a way that can be fired many thousands of times without wearing away the angle that catches and releases the striker. If you try to outsmart the connector angle or the nose curve, you'll more than likely wear away the angle and go selective-fire. The wearing away can also happen after taking out too much overtravel. It's been that way for 20+ years but if you've never heard of it, be aware.

[zipper046]

Since nobody was willing/able to answer the question, I figured it out for myself. I had epoxied a small spacer in the front of the... part. (firing pin mounting block?) It got rid of most of the take-up, and felt really good. However, as Flex pointed out, the trigger safety was now disengaged. I still did not know about the firing pin safety though. Here's how it's supposed to work: When the trigger is pulled back, a bump on the trigger bar pushes up a plunger in the slide that moves the block out of the way of the striker. If the trigger is pre-set too far back, the striker may be un-blocked with the trigger not being pulled.

So how do you check for this?

You need to see if the striker will move forward when the trigger is not being pulled. I removed the back plate from the slide and pulled the striker out. I removed the striker spring and re-installed the striker. I then installed the slide on the frame. With the back plate off, I should be able to push the striker forward until it either protrudes from the breechface, or is stopped by the firing pin safety. In my case, the safety was still working and stopped the striker. This leads me to think that if the trigger is not set back far enough to disengage the trigger safety, the firing pin safety should still be working properly.

I took a small file to the shim that I had installed to pre-set the trigger and started cutting it back. Now, my trigger moves forward just enough to reset the trigger safety. This may seem like a neat mod the first time you pull the trigger, but it doesn't really help much. The pre-travel won't be there after the first shot anyway. I think an overtravel adjustment would be much more benificial. I think I'll try the set screw on this one though. It would be much more adjustable, and more easily reversable.

Turn the gun upside down and look down through the magazine well with a pen light. You'll be able to see the drop safety and the part of the trigger bar that engages it. Slowly pull the trigger (while the gun is upside down) and you'll be able to see if it is engaging properly.

Z-

[the duck of death]

Thanks

[LPatterson]

*QUOTE*

For purposes of this clause, a “trigger

safety” is externally visible, and must

remain operable.

All I could find, what am I missing?

Duck,

you're missing language that allows you to modify the trigger safety.....

Read the first page of the interpretation very carefully -- if it's not listed as an approved modification, it's not legal. If anyone alleges that you're shooting an illegally modified blaster, the burden of proof rests on the you to demonstrate that all modifications are in fact permitted....

First page for easy reference:

NROI Interpretation for the Production Division Equipment Rules (Appendix D4)

June 25, 2009

General interpretation(s):

In accordance with the direction of the Board and their statement of intent with regard to Production Division equipment rules, NROI hereby issues the following

ruling:

External modifications continue to be strictly constrained to items specifically listed below.

Some specific classes of internal modifications are now specifically allowed, but in general internal modifications remain constrained to items specifically listed.

If a conflict appears to exist between these general statements and the listed details, below, the specifics listed in the notes and clarifications below shall be deemed definitive.

The burden of responsibility is on the shooter to ensure that his/her equipment is compliant with these provisions. If a modification is disputed – either by a Match Official or a competitor, under 11.1.2 and 11.7 – the competitor may be required to provide evidence of a specific clause in the rules or published NROI rulings which specifically authorizes the modification.

While the rules are currently silent on a Match Official’s authority to disassemble a competitor’s equipment, a competitor may – at any time – be required to prove that the equipment is compliant with the equipment rules, up to and including the disassembly of their equipment to verify compliance and proper function (e.g., the proper operation of factory safety mechanisms).

A competitor who cannot demonstrate that his/her equipment is compliant with these provisions will be moved to Open Division, under 6.2.5.1

Except as specifically modified below, all other clauses in Appendix D4 remain in effect, along with any applicable NROI rulings. In order to carry binding authority

in competition, an NROI ruling must be published in Front Sight and/or on the USPSA web-page.

Does that help?

Your posting of the interpretation is misleading because it doesn't mention springs and other parts which are replaceable,

[Nik Habicht]

*QUOTE*

For purposes of this clause, a “trigger

safety” is externally visible, and must

remain operable.

All I could find, what am I missing?

Duck,

you're missing language that allows you to modify the trigger safety.....

Read the first page of the interpretation very carefully -- if it's not listed as an approved modification, it's not legal. If anyone alleges that you're shooting an illegally modified blaster, the burden of proof rests on the you to demonstrate that all modifications are in fact permitted....

First page for easy reference:

NROI Interpretation for the Production Division Equipment Rules (Appendix D4)

June 25, 2009

General interpretation(s):

In accordance with the direction of the Board and their statement of intent with regard to Production Division equipment rules, NROI hereby issues the following

ruling:

External modifications continue to be strictly constrained to items specifically listed below.

Some specific classes of internal modifications are now specifically allowed, but in general internal modifications remain constrained to items specifically listed.

If a conflict appears to exist between these general statements and the listed details, below, the specifics listed in the notes and clarifications below shall be deemed definitive.

The burden of responsibility is on the shooter to ensure that his/her equipment is compliant with these provisions. If a modification is disputed – either by a Match Official or a competitor, under 11.1.2 and 11.7 – the competitor may be required to provide evidence of a specific clause in the rules or published NROI rulings which specifically authorizes the modification.

While the rules are currently silent on a Match Official’s authority to disassemble a competitor’s equipment, a competitor may – at any time – be required to prove that the equipment is compliant with the equipment rules, up to and including the disassembly of their equipment to verify compliance and proper function (e.g., the proper operation of factory safety mechanisms).

A competitor who cannot demonstrate that his/her equipment is compliant with these provisions will be moved to Open Division, under 6.2.5.1

Except as specifically modified below, all other clauses in Appendix D4 remain in effect, along with any applicable NROI rulings. In order to carry binding authority

in competition, an NROI ruling must be published in Front Sight and/or on the USPSA web-page.

Does that help?

Your posting of the interpretation is misleading because it doesn't mention springs and other parts which are replaceable,

Did you miss the part about the first page of the interpretation? Clearly there's more to follow the first page....

[the duck of death]

I'm still having trouble with this one. All the safeties work and the mod is not visable, why would it be prohibited?

[Nik Habicht]

I'm still having trouble with this one. All the safeties work and the mod is not visable, why would it be prohibited?

Because it's not specifically allowed.....

In any other division, if it's not prohibited, it's allowed. In Production, as part of the sweeping interpretation released last year, if things aren't expressly permitted, they are prohibited. There's no language allowing you to modify a trigger safety --- ergo, it's not legal to do so. Also, if anyone challenges it, the mods illegal (and you're shooting Open) until you convince an RM or an Arbitration panel that its in fact legal --- by pointing to plain English language specifically permitting the mod somewhere in the rules....

Will you get caught if you go through with the mod? I have no idea. I have an opinion on how I'll modify my blasters, and an opinion on what I'll do if I spot a blaster with an illegal mod....

I'm spending a bunch of time writing this stuff out, because a lot of people are still thinking it's business as usual (or as it used to be.) I don't want any one to get burnt at a major match because they weren't aware of the change in philosophy....

[the duck of death]

Got it, thanks again.