DISCLAIMER: THIS IS MY EXPERIENCE WITH VARIOUS GLOCK TRIGGERS AND COMPONENTS. ANY ATTEMPT TO MODIFY YOUR PISTOL MAY VOID YOU WARRANTY OR RESULT IN YOU BREAKING IT OR SHOOTING YOURSELF LIKE A MORON. DON'T TRY ANY OF THIS UNLESS YOU KNOW WHAT YOU ARE DOING.
I bought my first Glock in early 2003 just prior to leaving for Iraq. I didn't know much about them other than that some of the big kids I had been assigned to play OPFOR for carried a mix of 19s and 1911s. So I went to Shooters Supply in Fayetteville and bought a used Glock 19, Gen III, with Heinie sights and some gigantic paddle mag release. I thought it was the coolest thing ever, cause that's what the Varisty had. I also bought a Wilson 1911 worked on by who is by all rights my mentor, Larry Vickers. I wanted to believe that the 1911 was the end all, but I always found myself spending more time on the Glock than the Wilson. At 22 years old, and a young 11B, I wasn't an ideal candidate for a 1911. Truth be told, almost a decade later and having been issued a 1911 or Glock my whole pistol-toting time in the Army, I'm still not. Sure, I can legitimately maintain one now (thanks to LAV), I can shoot one well, and I love the craftsmanship and heritage that goes into a quality one. They have soul as people like to say. But I am also a realist, plus I like shooting my guns more than cleaning or maintaining them. Put yourself in a scenario where you've been forced to use your pistol and have fired 7 rounds. A target appears. What's faster, reloading under extreme stress or just pulling the trigger again...10 MORE TIMES? (thanks to Bob M. for that one) The Glock is the gun for me. I've got 32 of them now...
I have recently been witness to a host of issues with the Glock handgun by some of my more uneducated peers, and have seen countless examples by “the internet” giving bad advice on what makes a reliable duty trigger. Contrary to popular belief, not every commando is a gun guy. An even smaller fraction of those guys are knowledgeable firearms professionals, not just people who like guns. My goal here is to break the trigger down into it's separate components, to understand how modifying each one can change the characteristics of the trigger (and gun as a whole), and give people the tools to pick a safe, reliable combination of components that provide the performance they desire.
I will speak in terms of the 9/40/.357 “small frame” Glocks as that is what I am most familiar with, and the majority of Glock shooters will be using. Most of this carries over to the 20/21 as well. If you shoot a .45GAP, I pretend those don't exist so I can't help you, but the same guidance applies. This link can be followed to a Glock firearms diagram showing the 33 factory parts, I'll use these part numbers and nomenclature as a reference throughout this paper in case someone wants to order some new parts or has questions:
#25 Trigger with trigger bar
This part interacts with many of the other pieces that we will talk about, and most importantly is the part that interacts with your finger when you fire the Glock.
The Glock 17/22, 34/35, and 17L/24 comes with a smooth faced trigger. The 26/27 and 19/23 come with a trigger with vertically oriented serrations. I am not sure why, and most everyone I know prefers the smooth ones and frequently swap them out. Centrally located there is a simple trigger safety. Without pivoting out of the way upon contact with your finger, the trigger cannot physically move enough to fire the Glock.
Attached to this pivoting trigger is the trigger bar. The trigger bar is a piece of stamped steel that interacts with the internal components of the striker firing system in such a way that it deactivates the internal safeties and allows the striker to detonate the primer of an unfired cartridge. Working from the trigger back the first item of note on the trigger bar itself is a small lobe on top of the bar. This is the point where the trigger bar lifts part #8 (firing pin safety) out of the way. This is also commonly referred to as the striker block. When the trigger is depressed to the rear this lobe raises, pushing up on the firing pin safety and allowing free forward travel of the firing pin. This interaction is a key when performing a trigger job and will be addressed later. Moving to the rear, we come to the rear of the bar where it connects to the aptly named #23 (connector), the #24 (trigger spring), and #22 (trigger mechanism housing). The far rear protrusion on the back of the bar also retains, cocks, and releases the #4 (firing pin) as well.
Generally when a Glock shooter decides to change the mechanics of his trigger, the first thing they turn to is the trigger connector. The connector is a small piece of stamped metal that changes with weight of the trigger pull. It is pressed into the side of the trigger housing and a bent lip on the connector dictates the force required on the trigger bar to cock and release the firing pin.
***ALL OF THE FOLLOWING WEIGHTS AND FEELS ARE SUBJECTIVE FROM GUN TO GUN TO A DEGREE. THESE ARE STAMPED PARTS, NOT MACHINED AND ARE INCONSISTENT TO A DEGREE IN THEIR FEEL***
Glock has 3 of these from the factory that I recommend for use in duty/defensive guns. These are the standard (5.5lb), Minus (4.5lb) and Dot (Gen 4, 5lb-ish ??). Glock makes a couple more that rare and are unlikely to be a consideration, or too heavy to matter such as the 8.0lb (+) connector.
The standard connector comes in the subcompact guns (26 etc.), compact guns (19 etc.), and full-size guns (17 etc.). It used to be considered 5lbs by Glock but they now sell it as 5.5. It provides a decent pull once broken in and smoothed out. If you shoot it well as it comes or with a polish job it's a very reliable trigger.
The minus connector comes in the 35/35 and 17L/24 sized guns and offers a 4.5lb, formerly 3.5lb, pull as per Glock tech specs. When using otherwise factory components it also provides a reliable and shootable trigger.
The Dot connector is a new development to counter the redesigned trigger bar on the Gen 4 pistols. It is reported to be a middle ground between the standard and minus connectors due to increased weight brought on by Gen 4 trigger bars being changed slightly. When used in conjunction with the Gen 3 trigger bar they provide a slightly lighter, crisp break with an positive reset.
The only aftermarket connectors I have found to work well are the non-adjustable Ghost connectors, although I have heard anecdotal reports of the Lone Wolf connectors working well. Of particular note, the Scherer connectors are to be avoided at all costs. When in doubt, seek out Glock factory connectors.
This part is the fastest and easiest way to get a different trigger pull, and can be installed within a few minutes by any Glock shooter.
#24 Trigger Spring
***EDITED FOR CLARITY. IT MADE SENSE TO ME...SORRY"
The trigger spring is where the “give and take” of the trigger pull can be determined. The trigger spring connects the trigger bar to the trigger housing via a coiled “S” spring or plastic leaf spring with a captive coil spring (NY series). The interaction of the two springs is not exactly the same but as their basic functions are the so we'll skip the engineering lesson.
The heavier (sold as "lighter" due to their effects on the pull) the trigger spring, the lighter the trigger pull. The "lighter" spring makes it easier to apply force to the trigger and move the trigger bar, but as a result the "lighter" spring counters the movement of the trigger to reset. A "heavier" (actually lighter) spring results in a heavier trigger pull but the reduced resistance of the spring snaps the trigger back with more force.
I have found that I prefer the Glock factory trigger spring and the more positive reset. I give up no accuracy potential under rapid fire but gain a more positive reset and my splits show improvement with the slightly heavier trigger pull. This can be called shooter preference, but I encourage guys to go on the clock and find out for themselves. I used to be so preoccupied with a light trigger, then I did my due diligence and realized I was faster with the heavier trigger due to it's function after the shot broke.
The NY springs are popular with the (-) connectors to give a 5lb-ish pull with improved crispness over the standard factory setup and a very positive reset. To slightly lighten it, you can remove the coil spring from the olive plastic retainer and leave only the leaf-spring retainer in place. User beware, I do not advocate it but some shooters have found it to be functional. Moving to the standard connector AND NY spring is unacceptable for shooting performance. One of my friends is NYPD ESU and shoots a stock G19 with a Dept. mandate 12lb (!) trigger like a house on fire. He is the exception, not the rule.
#22 Trigger Mechanism Housing
This housing holds it all together as well as provides a home for your ejector. I don't modify it and only inspect it during detailed strips to make sure it hasn't cracked, warped, grown horns, or lost retention of the ejector. The key here is if you change it, make sure you have the proper ejector for 9 or 40 depending on what you shoot. This is also where you can take the pre-travel out of your trigger. I do not really recommend this unless it is professionally done so we'll not go into it. It is easy to screw it up and deactivate the safeties on the Glock if you are not a competent Glock gunsmith, resulting in potential injury, loss of life, legal fees, heckling, or an inability to defend yourself when you need that firearm the most. You wouldn't make your car go 5MPH faster if you knew it would deactivate the brakes, would you?
#6 Firing Pin Spring
This is almost always the cause of Failure to Fire issues with the Glock, and is the one I always see when my peers show me their new badd ass 1.5LB trigger. Primarily I see this with low end 9mm or USGI 9mm ball. The trigger pull is affected by this spring which is why it is included in the Wolff competition spring kit as well as many aftermarket drop in replacements. The firing pin goes back easier with these lightened springs hence lowering the pressure needing to be applied to the trigger to fire the Glock. The other shoe drops when you find out it goes forward with less force as well and it fails to ignite your primer and you wind up racking your slide rather than firing accurate, lethal shots on target. I DO NOT RECOMMEND YOU CHANGE THIS SPRING TO LIGHTER THAN THE FACTORY WEIGHT, PARTICULARLY IN 9MM GUNS. Just because I haven't had an issue with them detonating .40SW primers in my Federal EFMJ does no mean it will reliably detonate yours. I tried the Wolff competition spring kit in various 9MM guns and never had one that would reliably fire GI 9mm ball with the lightened firing pin spring.
#8 Firing Pin Safety (striker block)
#9 Firing Pin Safety Spring
The firing pin safety/spring is a key component in the safety and function of your pistol. The amount of force it takes to raise this block directly affects the force exerted on the trigger in order to fire the Glock. Without being raised out of the firing pin channel, the firing pin cannot travel forward to strike the primer. Also, the angle at which it engages the trigger bar directly affects the feel of the trigger pull. If the spring is lightened, the trigger bar has to exert less force on the block to get it out of the way. In other words, the trigger pull is lightened. I have had good luck replacing this spring with the Wolff competition spring. This is a place to alter the weight of your pull without the 2d/3d order effects of some of the other components. So long as the block travels freely and goes back down when the bar moves back to the reset position you are covered functionally. Modifications to the block itself will be covered during later. The block directly impacts how the trigger pull “feels” mechanically, and it can be altered to offer a smoother trigger pull.
#4 Firing Pin (striker)
The firing pin itself changes the trigger pull because of it's contact with the rearmost section of the trigger bar's horizontal section. The firing pin has a protrusion on the bottom which is the point where the trigger bar moves it to a fully cocked position before releasing it to strike the primer. Modification to this part will be covered later.
Mods to the Glock trigger system
I would like to treat this like a recipe book. My recipe for a Glock trigger is as follows, but there are more ways than this to make a reliable trigger for duty or defensive use. This one works for me but I am not married to it. So long as what you do works reliably and safely, there's no right answer for all of us. As a rule, I keep all dimensions and angles the same except for the firing pin block
-Smooth-faced Gen 3 trigger/bar
-Glock factory (-) connector
-Factory firing pin block
-Factory firing pin spring
-Wolff firing pin block spring (or factory, this is not too important to me)
-Factory trigger spring
-Factory trigger mechanism housing
-Factory firing pin (striker)
Trigger/Bar mods: Anywhere there is metal/metal contact I polish with flitz and brasso to a mirror shine. I do this using a dremel with a felt wheel, lower range RPMs, and lots of patience.
Connector: Same polishing as above, but I polish all surfaces of the bar since it's not very big.
Firing pin block: I round off the angles and mirror polish the whole unit. There are numerous tutorials online for this. If you overdo it, you'll be buying a new one. This creates less of a “wall” as the bar lifts the block and more of a gentle, smooth “hump”. I chuck mine up in a drill and contour it on a knife sharpener. I then polish it the same as the parts above. Remember, you can take more off but never add more on, and uniformity is your goal here.
Striker: I polish the protrusion on the bottom where it interacts with the trigger bar. This further ensures a smooth pull during the cocking and releasing of the firing pin by the trigger bar.
That's the magic. That and I shoot the shit out of them. The best trigger job you can do is put rounds down. Last but not least, if your trigger begins to get worse over time, not better, take it apart and clean it before you go spending money on parts. It's likely just gunked up and you'll be really pleased at the returns upon wiping it all down.