I am not sure a 1911 has a large enough port to chamber and eject a 9X25 cartridge, and I am not sure a 9X25 will fit into a 1911 magazine. Then you also have the issue of modifying the slide and the ejector for the smaller case head. I remember Colt had some issues when they made the Delta Elite in 10mm. Since the 9X25 is based on the 10mm case, it may be wiser to start with a pistol designed for the 10 mm, maybe even a Colt Delta Elite if you prefer the 1911 platform.