Best Glock 43X Upgrades 2026: Optics, Triggers, Mags & Barrels Ranked

Not every upgrade matters equally. This is the order that delivers the most improvement per dollar spent on a 43X MOS carry gun.

The 43X MOS ships with a Shield RMSc optic cut milled directly into the slide. This limits your optic choices to that specific footprint, but the upside is significant: direct mounting with no adapter plate means the optic sits as low as physically possible, keeping your sight picture clean and co-witnessCo-witness[Optics]Ability to see iron sights through a red dot or LPVO at 1x. Lower 1/3 co-witness is most common, placing the red dot above the iron sights for a cleaner view. achievable with suppressor-height iron sights.

All three picks below mount directly on the 43X MOS slide with no modifications. The Trijicon RMRcc also fits but at a higher price point ($500+) with less feature density than Holosun offerings. For a broader comparison of pistol red dots across all platforms, see our pistol red dot guide.

The 43X trigger market is much thinner than the G19 market. The 43X/48 uses a different trigger bar geometry, so most Glock 19 triggers physically will not fit. The Overwatch Precision DAT is the standout option: a flat-face, carry-safe trigger that drops in without fitting and delivers a meaningfully cleaner break and shorter reset than the factory trigger.

If $115 is too much, a trigger spring kit from companies like Ghost or NDP is a $20-30 option that reduces pull weight and smooths the trigger feel without replacing the trigger shoe itself. It is a compromise, but a noticeable improvement over factory for minimal investment.

A weapon light is non-negotiable on a home defense or nightstand gun. You cannot shoot what you cannot identify. The 43X has a slim accessory rail that accepts compact lights, but full-size options like the SureFire X300 create excessive overhang and destroy holster compatibility.

The Streamlight TLR-7 Sub is the default choice because it was designed for this exact use case: subcompact pistol rails. It sits flush on the 43X, produces 500 lumens (more than adequate for room-distance target identification), and has the widest holster support of any compact light. For a deeper comparison including full-size options, see our pistol lights guide.

The Shield Arms S15 is the most popular Glock 43X upgrade for a reason: it increases capacity from 10+1 to 15+1 with zero external dimension changes. The magazine uses a steel body with a staggered double-stack to single-feed design that fits flush in the 43X grip. From the outside, the gun looks and carries identically. From the inside, you have 50% more ammunition.

The catch (literally) is that the steel S15 body wears the factory polymer magazine release. You must buy the Shield Arms steel magazine catch ($35) to run S15 magazines long-term. Running S15 mags with the OEM catch will cause premature wear and eventual malfunctions. The steel catch is not optional.

Here is the honest take: we purchased S15 magazines but do not carry them defensively. The community reliability data is mixed. Many shooters report thousands of clean rounds with the Gen 3 S15, while others document feeding issues, particularly with hollow point ammunition. For a gun you might stake your life on, that uncertainty is not acceptable without extensive personal testing.

Our recommendation: buy S15 magazines for range and competition use. Carry with OEM 10-round Glock magazines until you have personally put 500+ rounds of your defensive ammunition through your specific S15 magazines without a single malfunction. If they pass that test, carry them. If they do not, you have excellent range magazines and your defensive reliability is uncompromised.

The Radian Ramjet + Afterburner ($389) is the premier barrel/compensator system for the 43X. It transforms the shooting experience: noticeably reduced recoil, improved practical accuracy, and a secure tapered barrel-to-comp interface that requires no thread locker and eliminates loosening concerns. It also works with the stock Glock recoil spring, so no tuning is needed.

Because the Ramjet barrel has no threads, the system is 50-state legal. States like California that restrict threaded barrels on semi-auto pistols are not an issue. The trade-offs are the standard compensator downsides: increased flash (especially with 115gr ammo), noise, and concussive blast. Read our hands-on Ramjet review for detailed 300-round test results, holster compatibility notes, and an honest breakdown of the defensive carry trade-offs. For a broader look at compensator options, see our Glock compensator guide.

Aftermarket slides are the least necessary upgrade for most 43X owners. The factory MOS slide already has an optic cut, and the functional improvements from aftermarket options (weight reduction, additional serrations, different optic footprints) are marginal compared to optics, triggers, and lights.

If you want a different optic footprint (RMR, 509T, ACRO) or a custom look, the Shield Arms S15 Optic-Ready Slide and ZEV Z43 Citadel are the primary options. Both offer multiple optic cut options and improved serrations. Budget $300-500 for a quality aftermarket slide, and factor in the cost of a new optic if you are switching footprints.

Every upgrade that changes the external dimensions of your 43X requires holster verification. An optic requires an optic-cut holster. A weapon light requires a light-bearing holster. A compensator adds barrel length.

The T.REX Arms Raptor accommodates the standard 43X with the Radian Ramjet installed without needing the Glock 48 or threaded-barrel holster option. The fit is clean. For other holster brands, verify compensator compatibility before ordering. Most quality Kydex holsters with an open bottom will handle the extra half-inch of barrel length.

For a complete breakdown of holster options for both stock and modified carry guns, see our concealed carry holster guide. You can also browse our pistol optic catalog to compare specs across all micro red dots.