McNally Drop-In Trigger Review For Gen-4 Glock 20 Part I

Posted: May 12, 2014 in Product Reviews
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This is the first installment in a two-part review of the McNally drop-in trigger, recently installed into my gen-4 Glock 20.  Mike from Ghost Targets was kind enough to do the install while I watched and took photos, so this post will cover installation and initial test shots with the trigger.

I previously had a Caylor Customs trigger job performed on the G20, which stopped the overtravel of the standard Glock trigger.  When the drop safety (the element of the trigger safety system that makes the Glock drop-safe, which is occasionally called a sear safety) disengages, it does so with a pretty substantial impulse.  Since the weight of the trigger pull is substantially more than the weight of the handgun, the combination of this impulse along with overtravel and grip angle causes the familiar tendency for the muzzle to drop that is so well-known for Glocks.  Eliminating overtravel along with good trigger control can dramatically improve your accuracy with a Glock.

The safety embedded into the trigger itself remained a bit of an issue since it does not fully depress (i.e. become flush with the actual trigger) during the firing cycle.  So, unless you apply a straight-back motion with the trigger finger, it is possible to place more pressure on one side of the trigger – typically the right side for a right-handed shooter.  Since the trigger is constrained to move along a straight line, this can result in moving the frame slightly left at trigger break.  I did notice this tendency a few times when drawing from the holster.

Although I had test-fired a McNally trigger in a G22 before, I really wanted to see how it performed in practice on my own firearm.  I want to thank Mike from Ghost Targets for setting me up with an evaluation trigger.

So, let’s get started with the install.  Here is my G20, cleared and ready for breakdown.  You will need an armorer’s tool, like the cool GlockTool marketed by Ghost Targets.



After removing the slide, remove the pins in the proper order along with the slide stop lever and locking block.  If you have seen T.R. Graham’s video or are already a Glock armorer, you can do this install in your sleep.  Detailed instructions are provided with the trigger.


The existing trigger pops right out.


and, the new trigger is ready to be dropped right in.


Here is what it looks like after drop-in.


Next, you re-install the locking block and slide lock.


There are two places where you may use an Allen wrench to adjust the updake and overtravel.  The trigger comes from the factory with zero overtravel.  Here is where you adjust the uptake.



You do not want to adjust this too tight or you can reach a point that it defaults part of the trigger safety system.


Personally, I’m an old-school revolver guy, so I learned trigger control as two stages – initial finger placement and slight pause followed by a single motion.  Even my first experiences with .22 LR pistols were with long, single-stage triggers.  So, a two-stage Glock trigger was always a three-stage motion for me.  Since I have always shot 1911’s rather well, I opted for a more 1911-style pull on the McNally.  If you are used to the standard uptake in a Glock trigger, I do not recommend changing it.

Once the firearm is completely re-assembled, you are ready to go.

So, how did it shoot?

I personally consider 8-10 yards to be the outer ring of my defensive radius.  I took a small Zombie target and ran it out to 8 yards at Eagle Gun range.  I loaded three rounds and then presented and fired in a controlled sequence as if all I had were just three shots to resolve a life-threatening situation.  Here is the result.


I got a little ahead of myself on the final shot and did not quite line up the sights before squeezing off the shot.  Sometimes this happens with indoor lighting as I have a bit of difficulty getting a perfect sight picture with my shades.  I shoot with the same sunglasses I wear outdoors most often since that is what I’m likely to be wearing in an actual defensive encounter.

So, that errant shot had nothing to do with the trigger and everything to do with the shooter.  Even so, that’s barely under a 1.5″ group at 8 yards, completely unsupported.

I also practice one-handed (right and left) and here are the results of a short session with ten rounds at 3 yards and ten rounds a four yards.


I have a bit of work to do on timing the trigger squeeze with wobble before I move onto longer distances.

So far, I’m pleased with the trigger and will report again after I put a few hundred more rounds downrange with the drop-in.  I have not experienced any issues with trigger reset to date.

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