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Glock 43X Optimized: Customizing the G43x

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The ongoing patchwork of COVID-19 lockdowns, quarantines, and shelter-in-place orders has led to a massive uptick in gun sales nationwide, with many of those buyers specifically purchasing guns for self-defense or personal protection. With smaller, slimmer pocket pistols being a natural choice for that particular application, we wanted to optimize one of the most popular entries in that class: the Glock 43X. Kitting this particular pistol out was a fairly daunting undertaking since there’s so much aftermarket for anything Glock related. But we put together a specific arrangement of add-ons that takes the G43X and morphs it into a pistol we’ve affectionately dubbed the “Glock 19 slim” as the result is a pocket pistol with the same length, capacity, and capability of even the best-appointed G19-sized carry guns. Historically, choosing a subcompact counterpart of a larger pistol comes with trade-offs in muzzle flip, effective range, and on-board ammo. But there are some unique upgrades to the Glock 43X specifically, which bridges the gap in all of these categories.

Glock 43x G43x Optimized Right


Perhaps the biggest update we could make to the diminutive G43X was a simple magazine swap. Factory-issue Glock magazines for the 43X/48 pistols are single-stack, 10-round mags. But the made-in-the-USA Shield Arms S15, metal-body mag holds 15 rounds in a flush-fit tube. This one change single-handedly boosts the Glock 43X by 50 percent and brings it on par with the capacity of most full-size service pistols. Furthermore, they’ve also released a +5 baseplate extension that further boosts the round count to 20, with about an inch of extra length. The only caveat that comes with using S15 magazines is that you need to change your magazine release button. The OEM plastic mag release will get chewed up in short order scraping against the thin-body metal mags. Shield Arms does produce their own button to fix this issue, but we used an aluminum piece from Hyve Technologies, which produces their own full line of Glock 43X accessories.

Mayhem Syndicate

Among those Hyve upgrades is a self-contained stainless steel guide rod and recoil spring unit. In addition to being more durable with less flex during recoil, the Hyve recoil unit also adds some extra weight to the front end of the pistol to reduce muzzle flip. 

In order to reduce muzzle flip as much as possible, we paired the stainless steel guide rod with a barrel/compensator combo unit from Mayhem Syndicate. While it’s far from the only Glock comp on the market, there are a couple things that set it apart. One is the size — Mayhem advertises that their 43X comp only increases length to the size of a G48/G19. The other is that they sell their comp mated to an in-house match-grade barrel that’s drilled for a roll pin. Using a pin, as opposed to just threads and thread locker, creates a more permanent attachment that’s just about impossible to shoot loose. At an MSRP of $350 for the barrel/comp package, it’s not the least-expensive option, but you do get a two-for-one enhancement out of it, in both increased accuracy out of the stainless match barrel and reduced muzzle flip with the comp. 

Glock 43x G43x optimized comp

The Mayhem Syndicate comp and Hyve’s heavier, stainless steel guide rod both help take the edge off of recoil.

We finished off the internals with a trigger kit from Johnny Custom Glocks. Johnny is a true artisan in the field of aftermarket triggers. He only has one product line — Glock triggers. We’ve been a huge fan of these triggers for years now, and the 43X/48 model didn’t disappoint. Ours features absolute minimal take-up with a hard break at 3¾ pounds almost every time (measured on a Lyman digital gauge) with a loud, tactile reset. The shoe is machined aluminum with a noticeably beefed-up safety tab that provides more positive engagement compared to OEM versions. 


Our top priority for outfitting the exterior of our test gun was to get a red-dot optics on it. The slim profile of the Glock 43X slide that makes it so carry-friendly also limits the selection of available optics to mount. We went with UK-based Shield PSD since their RMSc series is sized specifically for slimline and subcompact pistols. New for this year, Shield offers the RMSc with a glass lens upgrade, which we used in this build. We replaced the OEM sights with a high-contrast set of CAP sights from Handgun Combatives. These sights are produced by Ameriglo to the specifications of Handgun Combatives owner and lead instructor Dave Spaulding. The front sight is a 0.125-inch square notch painted with high-visibility paint with a small tritium dot in the center. The rear sight is a serrated black notch that measures 0.150 inch. One of the things we like about using Shield optics is that they sit low enough on the slide that suppressor height irons aren’t required to cowitness effectively. 

Since the OEM Glock slide doesn’t come cut for optics, we sourced a replacement slide from Grey Ghost Precision. This option is machined in-house and comes with front and rear serrations and some gentle lightening cuts and is available with a black, FDE, or gray DLC finish. 

Glock 43x G43x Optimized grip

Custom KG GunKote and frame work was performed by P4 Coatings.

We turned to the folks at P4 Coatings, who custom-blended a shade of KG GunKote to match the Grey Ghost slide to create a gray-on-bare-metal two-tone look. P4 also added medium texture to the front and backstraps of the frame, as well as a double undercut to the trigger guard.  


The concept was to optimize the Glock 43X for effective concealed carry and defensive use. To that point, there are some things to note, as it pertains to holsters, if you decide to run a setup like this. The first is the length increase. While the Mayhem comp isn’t particularly bulky, it does add some length. So a closed-end holster sized specifically for a 43X won’t allow you to seat the pistol, but Glock 48 holsters will fit perfectly. Also, if you’re running the Shield Arms S15 mags, they won’t fit in standard pouches. LAS Concealment mated an Archon Type B mag pouch to our G48 holster, and it worked without issue. 

LAS concealment g43x holster

The LAS Concealment Ronin 3.0 AIWB holster is comfortable and discreet.

[Editor's Note: This article first appeared in Concealment #18. Photos by Niccole Elizabeth.]


Grey Ghost Precision SPG43 Slide: $350 ($335 on Optics Planet, Click Here)G43x optimizedShield RMSc + Glass upgrade: $470
(Shield Sights now has Glass as a Standard Option)
Handgun Combatives G43X CAP sights: $75 (
Mayhem Syndicate G43X match barrel/carry comp combo: $350
Johnny Custom Glocks trigger kit: $290
Hyve Technologies extended mag release: $20
Hyve Technologies stainless steel recoil assembly: $49
Shield Arms S15 magazine: $40
Shield Arms S15 +5 baseplate kit: $40 (Find the Baseplates on Brownell's)
LAS Concealment Ronin 3.0 holster: $115


Grey Ghost Precision:
Shield Sights:
P4 Coatings:
Johnny Custom Glocks:
Handgun Combatives:
Hyve Technologies:
Mayhem Syndicate:
Shield Arms:
LAS Concealment:

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