Mossberg 930 SPX comes with a short Picatinny Rail on which the rear sight is mounted. I have gotten a Picatinny Riser that will allow me to shoot through the riser with the iron sights and mount a reflex sight on the elevated rail. My problem is that the Mossberg rail is too short to accommodate both the riser and the rear sight. Its about four inches long and at least 6 inches is needed. 8 inches would be better. Does anyone know if an 8 inch rail for the Mossberg 930 SPX is available anywhere?