I guess I should be clear, what does the .260 do that a 6.5X55 or 6.5X57 does not due better.. Other than that short action thing.
Here is a reply by Mule Deer, on the thread 260 vs swede vs creed:
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Mule Deer
I've owned multiple rifles in all three chamberings, and my take is this:
The 6.5x55 is capable of the same sort of accuracy as the other two, and can exceed their velocities slightly, since it has more powder room and normally comes in actions with plenty of room for seating bullets out. But the chambers and brass can vary considerably, and there aren't any full-power factory loads. Most American factory rifles (when available) only come with 1-9 twists.
Many .260's also come with 1-9 twists, but the chambers and brass are far more uniform (though brass quality can vary). Cases can also easily be made from various other .308-based rounds. But if you want to shoot very high ballistic-coefficient bullets the standard "short action" magazine is a little too short for optimum seating depth. If you onloy plan to use standard hunting bullets, it works fine. Factory loads tend to be limited these days.
The 6.5 Creedmoor solves the magazine length problem of the .260 by using a slightly shorter case with a wider, steeper shoulder. Brass quality is excellent, and the factory loads are very good, though sometimes hard to find. The 1-8 twist for ultra-long bullets is common, and every factory rifle I've shot in 6.5 Creedmoor has been VERY accurate with both factory ammo and handloads.
For the record, the only one I own a rifle for right now is the 6.5x55, but it's a custom rifle built on an FN Mauser 98 action with a 1-8 twits Lilja barrel, using a tight custom reamer. Most American factory ammo or brass won't fit in the chamber, but Lapua brass does. I've had it for a while, but if I hadn't would have kept the Ruger 77 Hawkeye in 6.5 Creedmoor I purchased the first year they came out, since it was just as accurate.
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John
Now that Remington is going with the 1/8 twist, things are a little different.
It might be argued that the 260 is better because of logistics in the USA, since you can use 243 brass or 308 brass or 7-08 brass and neck it up or down accordingly.
