We do not support Holosun sights, though 407C and 507C can work on our Glock MOS plates, as long as users use the short set of sight to plate screws, more info here: RMR sight to plate screws vs. Holosun screws
Arson Machine has been making our Glock, PDP and FN optics plates. We developed the Holosun 509T with Arson Machine back in 2021 but it was about the same time when we decided we would only make plates for sights made in USA or allied countries, it never saw the light of day. We've worked with David Carter at Arson Machine for years, Arson Machine makes many products for us: OPF-G, RMR, OPF-FN509T, RMR, OPF-PDP, RMR, OPF-PDP, DPP, OPF-G43X/48, RMRcc, ESF-H1, ESF-H, MFH, RSF-H, MSQ-H, it's a long list. We demand high quality and stringent QC, Arson consistently delivers both.
Arson Machine is bringing the 509T and 407K/EPS Glock MOS plates to the market.
407K/EPS plates are available now: https://arsonmachine.com/product/glock-mos-to-holosun-k-pattern-plate/
We will post the link to 509T plates as soon as Arson is ready to launch it.