# Does a Holosun 507C fit a Trijicon RMR cut?

**Verdict: Yes**

Yes. Holosun states the 507C uses the industry-standard RMR footprint, so it mounts to an RMR cut directly. The 507K is a different footprint.

Holosun says so on the product page itself: the 507C uses the "industry standard RMR footprint", which allows direct mounting to optics-ready slides cut for it. Where the slide is a genuine RMR cut, no adapter plate is involved.

- **Footprint** — Trijicon RMR pattern
- **Adapter plate on an RMR cut** — Not required
- **Holosun models sharing it** — 407C, 507C and 508T — the full-size open-emitter line
- **Holosun 509T (enclosed)** — NOT RMR footprint — needs Holosun’s own 509PLT-507C adapter plate

The confusions worth heading off are inside Holosun’s own range rather than between brands, and there are two. The 507C and the 507K differ by one letter and do not share a footprint — the K is the smaller sight built for subcompact slides and will not mount to an RMR cut. And if what you want is an ENCLOSED emitter, the 509T is not an RMR-footprint sight either: Holosun sells a 509PLT-507C plate precisely because it does not drop onto an RMR cut. Everything in the list above is open-emitter.

> **Caution:** A slide sold as "optics ready" is not automatically RMR-cut. Confirm the cut the manufacturer actually milled before ordering — the footprint has to match at both ends, and the sight sharing a pattern with the RMR says nothing about what is machined into your slide.

## Sources

- [Holosun HS507C-X2 — stated RMR footprint compatibility](https://www.holosun.com/products/hs507c-x2)
- [Trijicon RMR Type 2 — the sight the footprint is named after](https://www.trijicon.com/products/product-family/trijicon-rmr-RM06-RM07-RM09)
- [Holosun 509PLT-507C — the adapter the enclosed 509T needs for an RMR cut](https://www.holosun.com/products/509plt-507c)

## More on optics and mounting

- [Do Shield RMSc and Holosun K optics share a footprint?](https://www.tactgpt.app/answers/rmsc-and-holosun-k-footprint.md)
- [Will a Holosun 507K fit a Glock 43X MOS?](https://www.tactgpt.app/answers/holosun-507k-glock-43x-mos.md)
- [What red dot fits a SIG P365 without an adapter plate?](https://www.tactgpt.app/answers/sig-p365-red-dot-footprint.md)

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Last checked 2026-09-03. TactGPT can make mistakes. Always check important info for accuracy. The information it provides is intended for educational purposes only. It does not give legal advice; verify any laws cited. Always follow all applicable laws and safety guidelines.

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