If you are looking for a red dot or green dot optic for your Mossberg 940 then you are in luck! All the optics that will fit your "optics ready" Mossberg 940 can be found below at the best price with free shipping.

These optics will fit any of the Mossberg 940 models that have the optic cut machined into the top of the receiver. This is a "k-series" footprint cut, and will accept a K Series footprint optic or an RMSc footprint optic.

Most of these optics are on the smaller side. If you wanted the largest window optic that would fit then you would want the EPS Full Size found here.

As of writing this, the models that have the optic cut footprint are the Mossberg 940 JM Pro, the Mossberg 940 Pro Tactical, the Mossberg 940 Pro Turkey, and the Mossberg 940 Pro Waterfowl.