If you’re looking to mount a red dot on your Glock 43X MOS or Glock 48 MOS, the most important thing to know is this: only optics with the Shield RMSc footprint will fit directly onto the slide.
These slimline Glock models use a unique mounting system that doesn’t match the standard RMR / Venom / C-More footprint found on larger pistols. So unless you’re planning to use an adapter plate, you’ll want a red dot that uses the Shield RMSc footprint. That way, you can mount it directly to the slide with no extra parts or modifications.
Which Red Dots Fit?
Look specifically for optics that use the Shield RMSc footprint. This is the footprint that the Glock 43X and 48 MOS were designed around.
To make your choice easier, here are three solid red dot options that are all compatible—and each suits a different kind of user:
1. Vector Optics Frenzy-S 1x17x24 MOS Multi Reticle – Budget Versatile Option
- Why choose it: A great entry-level optic with multiple reticle options at a very competitive price point.
- Standout feature: Multi-reticle system, lightweight design, and auto shut-off to conserve battery life.
- Good for: Shooters looking for a budget-friendly, do-it-all red dot that works for both range and carry use.
2. Shield RMSx – Best for Sport and Competition Shooting
- Why choose it: Designed with a larger lens and faster dot acquisition in mind—perfect for competition use.
- Standout feature: Huge field of view in a lightweight package, with true RMSc mounting footprint.
- Good for: Sport shooting, competition, and fast-paced range work where speed and visibility matter.
3. Sightmark Mini Shot A-Spec M3 – Solid Everyday Carry Option
- Why choose it: Tough, compact, and built with concealed carry in mind.
- Standout feature: Aluminum housing, scratch-resistant lens, IP55-rated water resistance.
- Good for: EDC setups that need reliability without bulk. It’s durable, clean, and ready for daily use.
What About Holosun K-Series (407K/507K, EPS & EPS Carry)?
These are great red dots—but they don’t use the exact RMSc footprint. They won’t mount directly to a stock Glock 43X/48 MOS slide without an adapter plate, or slide modifications (which we don’t recommend).
If you really want to install any of the red dots that use the Holosun K-series footprint, make sure to get a proper adapter plate from RMSc footprint to K-series footprint, in order to ensure proper fit and function.
Summary
To keep things simple: Stick with red dots that use the Shield RMSc footprint for a true direct fit on the Glock 43X or 48 MOS.
Here are three great choices, depending on what you’re looking for:
- Vector Optics Frenzy-S – Budget-friendly and versatile for both range and carry
- Shield RMSx – Designed for speed and performance in sport shooting
- Sightmark Mini Shot A-Spec M3 – Tough and compact for everyday concealed carry
Choose the one that fits your needs, and you’ll have a red dot that pairs perfectly with your slimline Glock. If you need any advise after reading this article, just let us know and we get back to you.
