The Glock 43X and Glock 48 MOS pistols only accept RMSc-footprint optics, which makes the optic-selection problem narrower and cleaner than full-size Glock work. This isn't a 50-option category like the Glock 17 or Glock 19 lineup — there are maybe a dozen RMSc-pattern optics worth considering, and the right pick comes down to glass quality, dot crispness, battery life, and whether you want a circle-dot reticle or a clean dot. This guide picks the best red dot for Glock 43X and 48 based on the live RMSc inventory at 3CR Tactical.
What "RMSc Footprint" Actually Means for the 43X and 48
Both the Glock 43X MOS and Glock 48 MOS ship with a slide cut for the Shield RMSc footprint — narrow screw centerline, specific lug geometry, designed to fit on a subcompact-width slide that has no room for a wider RMR-pattern optic. The 43X and 48 use the same slide width and the same MOS plate geometry, so anything that bolts to one bolts to the other.
RMSc, Holosun K, and J-Point all share that footprint. Listings that say "RMSc / J-Point / Holosun K" all mean the same hole pattern. The Trijicon RMRcc is similar in size and intent but uses a slightly different screw and lug pattern — verify the RMRcc footprint before ordering; it is not interchangeable with RMSc.
Subcompact Optic Selection — What Actually Matters
On a subcompact carry pistol the same optic specs matter as on a full-size, but the priorities shift:
- Glass quality and dot crispness — small windows mean any optical distortion is more obvious
- Battery life — subcompact optics tend to use smaller batteries (CR1620 instead of CR2032) and the lower cell capacity makes battery life claims more important to verify
- Weight — a 43X is light to start with; an oversized optic ruins the balance
- Durability vs concealment — enclosed emitters add stack height and weight, which fight what made the 43X a carry gun in the first place; the math is less obvious than on a full-size
The Picks
Bushnell MPO-S Circle Dot — Best Reticle Concept for New Red Dot Shooters
The Bushnell MPO-S uses a circle-dot reticle (3 MOA dot inside a 50 MOA ring) on the RMSc footprint. The ring helps you pick up the optic fast under stress — it's much harder to "lose the dot" in the window — while the 3 MOA dot inside still lets you aim precisely. For a shooter transitioning from iron sights to a subcompact red dot, this is the easiest reticle to learn.
Price tier is mid-range; glass is competitive for the bracket. Inventory has been steady but limited — verify availability at the time of purchase.
Bushnell MPO Pro-S — Same Concept, Better Glass
The MPO Pro-S is the Pro-line variant of the same circle-dot reticle. Better glass clarity, brighter dot at maximum setting, premium pricing. If you like the circle-dot concept but want something closer to Trijicon-grade glass, this is the upgrade path.
Trijicon RMRcc — If You Don't Mind the Different Footprint
The Trijicon RMRcc with 3.25 MOA dot is purpose-built for subcompact slides. Trijicon glass quality, the proven RMR durability profile, and a smaller footprint than the standard RMR — but the RMRcc uses its own footprint, not RMSc. The 43X / 48 MOS factory cut is RMSc; running an RMRcc on a 43X or 48 means buying a slide milled for RMRcc, not the factory MOS slide.
Worth considering if you're already replacing the slide. Browse the Glock pistol optics selection alongside the slide options if you're going this route.
Shield Sights SMS / RMSc Slide Mount — When You Already Own a Shield Optic
The Shield Sights SMS/RMSc Slide Mount for Glock is the manufacturer's slide-mount solution for shooters already running a Shield optic. Pair it with a Shield RMSc, SMS, or any J-Point-pattern optic. Useful if you have a Shield optic already and want a direct mount path; not necessary if you're buying optic and mount together.
Battery Life — Where Subcompact Optics Differ Most
Most RMSc-class optics use a CR1620 cell because the housing has no room for a CR2032. The smaller cell drops total capacity, and manufacturer-claimed battery life is more variable than on full-size optics. Practical numbers from current production:
| Optic | Battery | Claimed Life (at moderate brightness) |
|---|---|---|
| Bushnell MPO-S Circle Dot | CR1632 | ~50,000 hours |
| Bushnell MPO Pro-S | CR1632 | ~50,000 hours |
| Trijicon RMRcc (3.25 MOA) | CR2032 | ~4 years |
| Shield SMS / RMSc | CR2032 | ~3 years (RMSc) |
Trijicon stays at CR2032 even on the RMRcc by engineering the housing around the larger cell, which is one reason the RMRcc weighs more than competing subcompact optics. The Bushnell MPO line uses a smaller cell but advertises long shake-awake battery life — actual real-world life depends heavily on how often the optic is in motion and which brightness setting is active.
Dot Crispness and Glass Quality
Small optic windows make dot quality more visible. A slightly fuzzy dot in a full-size RMR window can be ignored; the same dot quality in a 43X-size optic dominates your sight picture. Three reference points:
- Trijicon RMRcc — cleanest dot in the subcompact category, full daylight visibility, premium glass
- Bushnell MPO Pro-S — close behind Trijicon on dot quality, noticeable price savings
- Bushnell MPO-S (non-Pro) — dot quality is good for the price; visible difference from the Pro version at maximum brightness in direct sun
If you carry primarily indoors or in mixed lighting, the non-Pro options hold up fine. If you train outdoors in direct sun on a regular basis, budget for the Pro or RMRcc tier.
Suppressor-Height Sights for 43X / 48 Co-Witness
Once the optic is on the slide, your existing irons probably no longer co-witness through the optic window. Suppressor-height sight sets for the 43X / 48 family raise the iron sights enough to be visible through the RMSc optic. Selection in this category is narrower than for Glock 17/19 — verify in-stock at the time of purchase. The co-witness article in this series covers the geometry in detail.
If you want suppressor-height irons plus an optic in one package, the Nordic Components optic plate series (sized for full-size MOS) is the Glock 17/19 equivalent solution; the 43X / 48 don't have an exact analog in the current Nordic lineup. Most 43X / 48 buyers source the optic and the suppressor-height sights separately.
What Doesn't Fit on a 43X or 48
Some clarifications, because we field these questions every week:
- RMR Type 2 (full-size RMR) — does not fit. The slide is too narrow for the RMR housing. The 43X MOS slide is cut RMSc, not RMR.
- Aimpoint ACRO P2 — does not fit. Footprint and slide width are both wrong.
- Holosun 507c — does not fit. 507c uses the full-size RMR footprint.
- Holosun 407K / 507K — fits. These are RMSc-pattern (K footprint), interchangeable with RMSc-cut slides.
- Holosun EPS Carry — fits with adapter; the EPS Carry uses an RMSc-compatible mounting pattern, but specific adapter plates may be required for the 43X MOS slot vs an RMSc-direct cut.
Stripped vs Optic-Ready: Two Paths
You have two main paths to a red dot on a 43X or 48:
Path 1 — Factory MOS Slide With Adapter Plate
If you bought a Glock 43X MOS or 48 MOS from the factory, the slide already has the RMSc cut. Buy an RMSc-pattern optic, install it with the appropriate plate or hardware, done. This is the cheapest path.
Path 2 — Aftermarket Slide Cut for the Optic You Want
If you have a non-MOS 43 or 43X and want a red dot, you need an aftermarket slide. Options in stock:
- LFA Elite RMSc Stripped Slide for Glock 43/43X — stripped Cerakote slide, build it out with your choice of barrel and parts
- LFA Combat RMSc Slide for Glock 43 — Combat-series stripped slide with serration package
- LFA Combat X RMSc Slide for Glock 48 — 48-specific variant
All three are RMSc-cut. Mount the optic of your choice directly on the slide. No adapter plate needed.
Where to Go From Here
If you've already settled on RMSc as your footprint and just need an optic, the pistol optics category filtered by Compatibility shows everything we cut for RMSc / K / J-Point. If you're still deciding between footprint families across multiple pistols, start with the footprint guide. For the 43X and 48 specifically, the Bushnell MPO-S Circle Dot is the easiest first red dot; the MPO Pro-S is the upgrade path with better glass; the RMRcc is the premium path if you're already replacing the slide.
DISCLAIMER: "GLOCK" is a federally registered trademark of GLOCK, Inc. and is one of many trademarks owned by GLOCK, Inc. and GLOCK Ges.m.b.H. Neither 3CR Tactical nor this site are affiliated in any manner with, or otherwise endorsed by, GLOCK, Inc. or GLOCK Ges.m.b.H. The use of "GLOCK" on this page is merely to advertise the sale of GLOCK pistols, parts, or components. For additional genuine GLOCK, Inc. and GLOCK Ges.m.b.H products and parts visit www.glock.com.