Came across a 1903A4 with a SC barrel 12-42. After taking off the handguard I found the markings on the top of the barrel RBLT. O.B.S. 3 with 9. 4. 45. under it. The rifle and all it's parts had been parked, replacement stock and HG. It came to me at a gun show from a retired Marine. I didn't get any story with it but that he got it from an older Marine that had given him some weapons he had had from WW2.