Holosun 507K X2 mount?

[david walter]

Have an extra I want to mount 45* on an AR as a backup, but am having trouble deciphering which base it fits on?

I know it fits a Sig 365 XL, if that helps. My other one is on that.

 

[Mute]

The K model Holosuns have their own pattern. It's closest to the Shield rmsc but it doesn't have a cutout for the rear nubs and the cutout for the front are shallower. This link should give you a better idea of what I'm talking about:

Footprints/Mounting Standards on Red Dot Sights - Optics Trade Blog

In this article, the most common footprints/mounting standards used on red dot sights are listed. Each standard is described and an image of it is added.

optics-info.com

If you haven't already bought your mount, I know Arisaka makes a 45 degree mount with adaptable plates including a plate for the 407/507K.