Scope Mount Finder

Fit a Holosun 509T on an RMR slide cut

How the enclosed Holosun 509T reaches an RMR cut, and why it needs its adapter plate.

Needs adapterThe Holosun 509T has a unique footprint but comes with an adapter plate that mounts it on an RMR cut. Fit that plate, or an RMR-cut slide, to run it.
OpticHolosun 509T enclosed dot509T proprietary footprint
interface
Mount509T to RMR adapter plate (supplied)
seats on
RailTrijicon RMR slide cutRMR footprint
Fit readoutBench figures
Fitment
Native footprint
509T is its own pattern, not RMR
Bridge
the supplied 509T-to-RMR adapter plate
What to fit it with

The 509T is an enclosed dot on its own footprint, not the open RMR pattern. Holosun supplies an adapter plate that carries the 509T on an RMR cut, so an RMR-cut slide or an RMR Picatinny mount will take it with the plate fitted.

Without the adapter plate the 509T will not sit on an RMR cut. Keep the plate with the optic, since the sight cannot mount to a bare RMR pattern on its own.

Related fitments

Sources: Red dot footprint families, OpticFootprint · Guide to red dot footprints, OpticsPlanet · Red dot footprint compatibility guide, Athena Precision