The Co-witness Ready Optic Mount (CROM) is a direct mount for attaching a Trijicon RMR to your Mossberg shotgun. Using the existing drilled and tapped hole pattern found on many factory Mossberg 500s, 590s, and 930s, the mount eliminates the need for a picatinny rail by directly mounting the optic to the receiver. This allows the optic to sit much lower, providing a consistent and proper cheek weld.

The CROM utilizes an XS rear ghost ring that is adjustable for both windage and elevation. This gives you the ability to co-witness the rear ghost ring and an appropriately sized front sight with the red dot, allowing an emergency backup sighting system in case of optic failure. Front sights from XS, Wilson Combat, Vang Comp, etc that are designed to work with ghost rings will be compatible with the CROM’s rear aperture. Front sights with a height over bore (top of the inside of the barrel to the top of the front sight) of approximately 0.75″ should be able to achieve a usable co-witness. The height of the CROM aperture is designed around the factory front ghost ring sight of the Mossberg 590a1.

If your Mossberg shotgun is not drilled and tapped using the Mossberg pattern, consult a qualified gunsmith.

Made in the U.S.A

Note: The zero of a shotgun is very dependent on the specific barrel and ammunition used. While the XS rear sight allows for a wide range of adjustment, it is possible you may need a taller or shorter front sight depending on where your specific gun and ammo hits. We cannot guarantee that every shooter will be able to achieve a perfect co-witness with their exact setup, we can only offer guidleines based on what we have seen in testing.