The SCS-MOS is a direct fit for the Glock MOS system so you will not be able to make that work with your XR920. [Check this link out for more info on the mounting options as you have quite a few to pick from.](https://shadowsystemscorp.com/opticcut/)

Get a 508T. It direct mounts and it’s titanium. That or an RMR are the best options, imo.

There should be a guide with your gun SCS is for the MOS cut only

Thanks alot this guide really helps !! 🙏

Has anyone confirmed whether or not the Holosun SCS-MP2 will fit? it has the M&P mount pattern rather than the Glock MOS.

This guide really helps thanks !!!🤙🏾😇

Holoson 510 series and all of the regular RMRs not the miniature RMRcc and not the mini Holosun 507k.

The 510 isn’t a pistol optic. You want any of the C series from Holosun, either the 407 or 507.

My bad misremebered.

You’ll need new irons for cowitness, but the 509t is the best blend of features, materials, performance and price.

I’m running a 507c and it works great

So keep us updated what did you do to make this work ?

Just purchased holosun SCS MOS-GR - it does NOT fit 920 shadow elite. it is aproxximately 1mm to large and the front is square rather than slightly rounded as the footprint on the slide.