The RMRcc wants an adapter plate with the 43x/forty eight MOS, which places the sight basically along with the slide. It does not sit within the slot in any respect. If someone would like just the RMRcc about the 43x or 48 it would be the only time I, Individually, https://glock-43x-mos-price37902.blogpayz.com/18343579/a-simple-key-for-glock-43x-mos-slide-unveiled