Something does not sound right. ANY 101xxx would be a Model 1896 (the Model 1898 did not start until around 109000 - and - military Krag barrels (unlike those for the 1903) are completely un-marked.

Do you perhaps have an 1895 Winchester lever action? Many were made in .30-40, their barrels ARE, I believe, marked ".30 U.S." when so chambered, and, an offset scope WOULD be required there as well (both guns eject fired cases straight up). Sadly, the scope pretty well destroys any collector value, if the mounting was accomplished by drilling holes.