'Kenserres - Welcome to the KCA Forum.

If I understand correctly, you recently purchased a U.S. model 1898 Krag rifle and its rear sight is not completely original.

If you post some pictures of your rifle's hand-guard and rear-sight base, KCA members can tell you which parts or model sight you need to complete your model 1898 rifle.

Most likely your Krag had a model 1901 or model 1902 rear sight. The model 1896 sight is also a remote possibility. (The model 1898 rear sight is unlikely, because these were removed when the higher velocity 2,200 fps ammo was abandoned).

As others have stated, the rear-sights have specific wood hand-guards. The different models of sights require different openings in the hand-guard.