6.5 Differences?

[Twicepop]

What if any are the physical differences between the 6.5x55 Swedish Mauser and the 6.5x55 SKAN? Is it two separate cartridges with the same dimensions like the .223 Remington and the 5.56 NATO?

 

[Laurie]

The SKAN is a 'regularised' version to ensure all participants in Scandinavian regional international matches have common chambers in their rifles and ammunition dimensioned to suit. Although the cartridge was a joint Norwegian / Swedish venture in the 1890s with one set of agreed dimensions it seems that differing national interpretations of the drawings (presumably around tolerances) led to slightly different production versions. The competitions in question use issued arsenal ammunition provided by the host nation and on occasions these variations allegedly caused mismatches giving slightly hard chambering and/or reduced precision for some competitors and 'visitors' could be disadvantaged as a result against the home team.

When the Scandinavian nations adopted the Sauer 200 STR in the 1990s as the sole standard match rifle for regional matches in the various disciplines involved, it was decided to settle on a single set of (presumably tighter toleranced) dimensions that Sauer would adopt for its 6.5X55 chambers and all participating countries' ammunition manufacturers would use for cases.

https://en.wikipedia.org/wiki/SIG_Sauer_200_STR

It is often believed that the SKAN allows higher pressures than the 'Swedish Mauser', but the controlling authority is the European CIP and its standard is the 6.5X55mm SE, the higher pressure 55,000 psi MAP version of the cartridge which is not recommended for use in older military rifles, especially the Norwegian Krag. The SKAN conforms exactly to this standard.

I've read that true 6.5X55 SKAN dies may size brass to very slightly different dimensions compared to standard 6.5X55 SE versions and this occasionally causes chambering issues in commercial rifles. Working from memory (bad idea) I believe if there is an issue it results from marginally insufficient shoulder 'bump' for a minimum headspace SE chamber.