The BoMar BMCS cut differs from the standard BoMar cut. In that, in the BMCS cut, the rear sight's elevation screw fits directly into threads cut into the top of the pistol's slide.
Sight Details:
Things to Remember!

If the Dawson Precision® recommended sights do not zero your pistol, we will give you one new front sight that has the required height to correct the point of impact to your specification, free of charge. (Dawson Precision's Perfect Impact® Promise)