Ol' Joe nailed it dead on.
Are their other rounds in the 6.5x55 that would not shoot or should not be shot out of the 6.5x55 Swede?
There MAY be another cartridge that uses a 6.5mm bullet, but has a different case length, shoulder angle, etc out there (in fact, I know there are several rounds that use the 6.5mm bullet, with different case dimentions)that would obviously be potentially unsafe to fire in a Swede Mauser.
Also, there MAY even be a round that uses a 6.5mm bullet, with a case length that happens to also be 55mm long, but it would have a different name/designation, and the shoulder, case width, or
something would be different, like a 6.5x55 "improved", or something like that (dont know if there really is a 6.5x55 Ackley Improved, or another wildcat that is the same bullet and case length, but with just a different shoulder angle, neck length, or something, but it's pretty likely I'd think)
Hope that made sense, and didnt add any confusion. Like O'l' Joe said, a cartridge named ONLY (IE-no "AI" or "improved" or similar also in the name) "6.5x55", or "6.5 Swede" is what you want for the Swede Mauser, and those to designations are the same round, just said 2 ways. Sometimes ammo dealers list it as one or the other, or somethimes have both "names" shown, but like he said, its the same thing, and the "55" is the case length. Pretty standard European/metric cartidge designation.
