What's the difference?

The 6,5x55 was constructed as a result of a cooperation between the Norwegian and Swedish gouvernment/army. The Norwegians used it in their Norwegian Krag Jørgensen at a certain preassure, while the Swedes used a slightly higher preassure for their model 96. At some point the headspace dimentiones got mixed up, the Swedes used the go gauge, while the Norwegians used the no-go gauge. The Skan is a new standard of headspace in the middle of the old go and no-go. All other dimentions are equal. Both old versions can be fired in the SKAN-chamber.

The Swedish version with the highest preassure became most used and known , therfore it is called the 6,5x55 Swedish Mauser, but the correct name of the cartridge is simply:6,5x55

Thats was nice, and now please tell us about the 6.5mmx55 Ackley Imp 40 degree vs 6.5mmx55 SKAN

Vh
Malcolm

That's easy, the 6.5 SKAN is for all intents and purposes no different than the 6.5 swede (balistically). While the Improved round is just what it says: It follows along the same pattern as the .257 AI, the .280 AI, etc. Blown out case, 40 degree shoulder, etc. It is comproable balistically to the 6.5x257 imp. and just a tad behind the 6.5x284.