Chad S. - The great majority of U. S. Krags do not have their serial numbers showing up in existing records.  Several hundred of the numbers that are recorded were for rifles that were destroyed at Cumberland Depot in Pa.
  It would be interesting to know which model of rear sight is currently on your Krag.  It is likely your rifle's sight was updated when different models came in to use.  Each sight model required a different wood hand-guard.  (Here are photos of likely sights:  model 1896, 1901 and 1902).

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