Glock 43X MOS Guide
Introduction
The Glock 43X MOS is one of the most popular slimline pistols for concealed carry. It combines the compact size of the 43X platform with Glock’s Modular Optic System (MOS), allowing users to mount a micro red dot sight directly onto the slide.
However, not every optic fits the Glock 43X MOS. This guide explains compatibility, footprint standards, and the best optic choices for this platform.
What Is Glock 43X MOS?
The Glock 43X MOS is an optic-ready version of the standard Glock 43X. It features a factory-cut slide designed to accept micro red dot sights using the RMSc footprint system.
This makes it ideal for:
- Concealed carry users
- Everyday carry (EDC) setups
- Lightweight pistol builds
Glock 43X MOS Footprint Compatibility
The Glock 43X MOS is primarily designed for the:
RMSc Footprint System
This is the key compatibility standard for this platform.
Compatible RMSc optics include:
- Shield RMSc
- Holosun 407K
- Holosun 507K
- Holosun EPS Carry series
These optics are compact enough to match the slim slide profile of the 43X MOS.
Can You Use RMR Footprint Optics on Glock 43X MOS?
In most cases:
- ❌ RMR footprint optics do NOT directly fit Glock 43X MOS
- ⚠️ Adapter plates may allow mounting, but are not ideal
- ❌ Full-size optics are too large for the slide geometry
Why?
The 43X MOS slide is designed specifically for compact optics, not full-size duty red dots.
Best Red Dot Setup for Glock 43X MOS
Recommended configuration:
- RMSc footprint red dot sight
- Compact or enclosed emitter design
- Low-profile mounting for co-witness compatibility
Best use cases:
- Concealed carry
- Self-defense
- Everyday carry reliability
Open vs Enclosed Emitter on Glock 43X MOS
Open emitter optics:
- Lighter weight
- Wider field of view
- More common in compact optics
Enclosed emitter optics:
- Better protection from dust, rain, and debris
- More durable for harsh environments
- Slightly larger footprint
👉 For EDC use, both are valid, but enclosed emitters offer better long-term durability.
Do You Need a Plate for Glock 43X MOS?
It depends on the optic:
- RMSc footprint optics → usually direct mount or minimal plate
- Some optics → require Glock MOS-specific adapter plate
- Non-RMSc optics → not recommended without modification
Always confirm footprint compatibility before installation.
Common Mistakes to Avoid
❌ Buying full-size optics
The 43X MOS is not designed for RMR footprint optics.
❌ Ignoring footprint standards
Always match RMSc-compatible optics.
❌ Using incorrect screws or torque
Improper installation can cause zero shift or damage.
How to Choose the Right Optic for Glock 43X MOS
Ask yourself:
1. Is it RMSc footprint?
If yes → it will likely fit.
2. Is it compact enough for concealed carry?
Bigger optics reduce concealability.
3. Do you prefer durability or weight savings?
- Enclosed emitter → durability
- Open emitter → lighter weight
Recommended Optic Setup Summary
Best-performing configurations for Glock 43X MOS:
- RMSc footprint red dot sight
- Compact or micro-sized optic body
- Concealed carry optimized setup
Related Guides
To better understand optic compatibility, you may also read:
- What Is RMSc Footprint
- RMR vs RMSc: Differences Explained
- Glock MOS Optic Compatibility Guide
- How To Zero a Red Dot Sight
Final Thoughts
The Glock 43X MOS is specifically designed around the RMSc footprint system, making it one of the best platforms for compact red dot sights.
Choosing the correct optic ensures reliable performance, better concealability, and easier installation.
