I'm not sure if a rmr will fit, but vortex Venoms and burris FF3 are another option. And those do fit on the Raptors.
Although I do not use them on my 686's. I have a Vortex Venom on my 629 44 magnum and 929 9mm. Those have 3moa dots and can handle heavy magnum loads.
The allchin mount seems like it's more accepting other models? It's a tad bit taller than the Raptor, but looks about the same.
The Nikon P tactical spur had its own mounts made by Raptor engineering and weren't interchangeable with the vortex Venom mounts. The Nikon is a bit wider. So, the mount for the regular Raptor wouldn't work. I never tried the Allchin mounts for them. But I don't think they'll work.
Pictured below. One of my Raptor/ Venom guns. And a comparison picture of an Allchin mount and a Raptor, side by side.