Hotwire:  Welcome to the KCA forum!
  Parashooter is knowledgeable and correct.  I believe that marking was used by the Norwegian steel or barrel supplier and it is commonly seen on early 'Konsberg Krags'.
  The 'swastika' was an ancient symbol used by many cultures.  Early books by Rudyard Kipling will have it beneath the author's name.  I have seen it on old American poker chips, a sign for 'Good Luck'.  I believe it was used by western 'Native Americans' and in India.  The Nazis ruined a perfectly good symbol!
  As Dick Hosmer related, your rifle is probably in 6.5X55mm 'Swedish Mauser'.  (The WW2 occupation Norwegian Krags will have the Nazi Eagle and swastika).
  It is hard to find Norwegian Krags with nice shiny bores.  The barrels have a left hand thread, so re-barreling would be a challenge.  Hopefully your bore 'cleans up'.  A good Norwegian bore would look like any other good bore.  In my experience, a rough 6.5mm bore will often cause heavy 160 grain bullets to tumble, but, may shoot 139 grain bullets very well.  Unaltered Norwegian Krags are a desirable rifle.  If you post pictures and a serial number, you will get more information.