Word of advice on the 43X MOS and the 48 MOS. If you mount your red dot and then have problems with shells being ejected, the problem is not with the gun. It is with the length of the mounting screws for your red dot. Specifically, the length of the right screw when looking down from the top with the gun pointed forward. The screw is extending too far into the slide and effecting the function of the ejector. Grind the screw down about 1/8" and it will fix the problem. I had that problem with my 43X and found this quick fix online. It worked!