Pictures would be a great help. The Springfield made Krag was modified to fire blanks...whether by Springfield or a movie studio is unclear. I did see several of them with the modification you describe at the CMP at Anniston, AL several years ago. The rumor at the time was that the CMP Director traded M1903 A3 Drill rifles for the Krags. Many of the Krags had movie studio markings such as MGM and RKO stamped on them.