The Allchin mount for an RMR or Holosun fits perfectly. I would recommend one. The Allchin mount for a Vortex Venom, not so much. It fits the pistol well using all three mounting holes on an S&W but doesn’t fit the red dot well and it works loose.

The EGW mount for the Venom only uses ONE of the S&W tapped mounting screws and it worked loose on mine. It fit the red dot great, just not the pistol. They need to add another mounting hole for ow it attaches to the revolver, in my view.

I wish there were other options out there.