From the Nationmaster Encyclopedia:  Part 1 of 2

6.5x55 (also known as 6.5x55 Krag, 6.5x55 Swedish Mauser, 6,5x55 Mauser and 6.5x55 Scan), was developed by a Norwegian-Swedish committee in 1891 for use in the new rifles then under consideration in the United kingdom of Sweden and Norway. Norway adopted the Krag-Jørgensen, while Sweden adopted a Mauser rifle. Sweden and Norway 1888 The Union between Sweden and Norway refers to the kingdoms of Sweden and Norway between 1814 and 1905, when they were united under one monarch in a personal union, following the Convention of Moss, on August 14, and the Norwegian constitutional revision of November 4. ... The Krag-Jørgensen is a repeating bolt action rifle designed by the Norwegians Ole Herman Johannes Krag and Erik Jørgensen in the late 19th century. ... Mauser is the common name of a German arms manufacturer, maker of a line of bolt-action rifles from the 1870s to present. ...

Due to different interpretations of the standard, i.e. the standards of manufacturing using maximum chamber in the Krag vs. minimum chamber in the Swedish Mauser, a small percentage of the ammunition produced in Norway required a heavy push on the bolt handle to chamber in the Swedish gun. After the rumor of this difference first surfaced in 1900, it was examined by the Swedish military. They declared the difference to be insignificant, and that both the Swedish and Norwegian ammunition was within the specified parameters laid down. Despite this finding, the Swedish weapon-historian Josef Alm repeated the rumour in a book in the 1930s, leading many to believe that there was a significant difference between the two types of ammunition.