Footprints, Mounting and Norsso Optic Cuts

Hi y’all, Lee here with a quick reference guide to Holosun pistol optics and optic footprints.

The Holosun lineup has expanded significantly, and keeping track of the different models can get confusing. In some cases, a single letter in the model name can mean the difference between a compatible optic and one that requires a completely different mounting solution.

For example, the “C” and “K” models use different footprints, so understanding which optic you're working with is critical when choosing an aftermarket pistol slide.

Our team at Norsso put together this guide to help you navigate the Holosun catalog and determine which optics are compatible with the Norsso optic cuts available for our slides.

 

Holosun Optic Footprint Compatibility

The charts above provide a general reference for Holosun pistol reflex sights, including their features and compatible footprints.

However, understanding the footprint is only part of the equation.

When selecting an aftermarket slide, you also need to consider how the optic is mounted, what hardware is required, and whether the slide has enough material to support the desired optic cut.

That's where a properly engineered direct-mount optic solution can make a difference.

Why Choose a Custom Optic Cut?

At Norsso, we've engineered our slides to allow many popular optics to mount directly to the slide without relying on an adapter plate.

We generally prefer direct mounting because it can help minimize mechanical offset and provide a more secure mounting interface.

Think of the slide like a tailored suit. Instead of using a universal adapter to make one optic fit multiple footprints, the slide can be machined specifically for the optic you intend to use.

The tradeoff is versatility.

An adapter plate can allow a single slide to accommodate multiple optic footprints, while a direct-milled optic cut is designed around a specific footprint. For a dedicated build, however, we believe a direct-mount solution provides significant advantages. 

Mounting a Red Dot Optic on a Pistol

If you're new to mounting red dot optics on pistols, there is one important consideration to understand: there is limited space inside a pistol slide.

An optic cut can sometimes come very close to internal slide components. The mounting screws supplied with an optic are designed to accommodate a variety of mounting configurations, but they cannot account for every aftermarket slide and every possible optic-cut geometry.

As a result, the screws included with an optic may sometimes need to be shortened for a particular direct-mount application.

Using incorrect screw length can interfere with the internal operation of the slide, which is why proper hardware selection is extremely important.

Always verify screw length, thread engagement, and internal clearance for your specific slide and optic combination before installation.

Check out this video here to understand more about the impact of not using the correct hardware:

https://youtu.be/25_tFSnHx3w

Norsso Direct-Mount Optic Cut Solutions

Norsso offers a variety of optic cuts designed to directly mount popular pistol red dots.

Below is a quick reference for some of the optic-cut solutions available across our platforms.

Glock Standard Width Frame (e.g. Glock 17, 19, 26, 22, 23, 27)”

Optic Cut	Compatible Optics	Notes
Trijicon RMR/Holosun 507C	Holosun 407C/507C/508T/507Comp	Use short screw on right side
RMSc Shield/507K/EPS	Holosun 407K/507K/EPS*/EPS Carry	* The Full size EPS comes with an adapter plate, you’ll need screws from here to mount directly to the slide: https://norsso.com/parts/hardware/optic-mount-screws/calculated-kinetics-m4-x-9-25mm-screws/
Holosun 509T	Holosun 509T	We mill the rail feature to directly mount the optic
Holosun SCS320	Holosun SCS320	Right side screw may have to be shortened. This is the Deltapoint Pro footprint with a rear sight dovetail.
Holosun SCSMOS	Holosun SCSMOS	Slide comes with shorter mounting screws

 

SIG P320 (all sizes)

Optic Cut	Compatible Optics	Notes
Trijicon RMR/Holosun 507C	Holosun 407C/507C/508T/507Comp
RMSc Shield/507K/EPS	Holosun 407K/507K/EPS*/EPS Carry	* The Full size EPS comes with an adapter plate, you’ll need screws from here to mount directly to the slide: https://norsso.com/parts/hardware/optic-mount-screws/calculated-kinetics-m4-x-9-25mm-screws/
Holosun 509T	Holosun 509T	We mill the rail feature to directly mount the optic
RomeoX Pro/Holosun SCS320	Holosun SCS320

 

 

SIG P365 or Glock 43 (micro optics)

Optic Cut	Compatible Optics	Notes
RMSc Shield/507K/EPS	Holosun 407K/507K/EPS*/EPS Carry/SCS Carry	* The Full size EPS comes with an adapter plate, you’ll need screws from here to mount directly to the slide: https://norsso.com/parts/hardware/optic-mount-screws/calculated-kinetics-m4-x-9-25mm-screws/

 

Why 17-4 Stainless Steel Matters for Norsso Optic Cuts

One of the reasons Norsso can offer this range of direct-mount optic solutions is the way we manufacture our slides.

Our slides are machined from solid 17-4 stainless steel billet.

That gives us the material necessary to machine specialized optic cuts and configurations that may not be possible with existing factory slides or other aftermarket slides that lack sufficient material in the appropriate areas.

When designing a slide around a specific optic, having enough material isn't simply about appearance. The optic cut needs to be engineered around the slide's overall geometry, mounting interface, and internal components.

Choose the Right Holosun Optic Cut for Your Build

Understanding Holosun model numbers and footprints is essential when selecting an aftermarket slide.

The difference between a Holosun 507C and 507K, for example, isn't simply size or appearance—the two optics use different mounting footprints.

Before ordering a Norsso slide, identify the exact optic model you're using and select the corresponding optic-cut configuration.

If you're planning a custom build and aren't sure which Norsso optic cut or mounting hardware you need, contact the Norsso team for assistance.

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