Ramblin Razorback,
Well said.
It also depends, of course, on the "long" action. In my experience the 6.5x55 is perfect in what's generally considered a .30-06 length action, NOT the extra-long actions of many made today, such as the Remington 700. The .30-06 length magazine of about 3.35 inches leaves plenty room for ultra-long 140's auch as the Berger VLD, even more than the 6.5 Creedmoor provides in a short action.
One of my 6.5x55's was a Ruger 77 Mark II, and Ruger is one of the few American companies still making true .30-06 length action. It was super-accurate, with plenty of flexibility for bullet seating, but like a rifle-loony nitwit, after a few years I sold it. Built another with a 1-8 twist Lilja on a commercial FN 98 action a few years later, which does the same things (and has a nicer New Zealand walnut stock) but could have easily just stuck with the Ruger.
The 6.5x55 recoils noticeably less than .30-06 length American cartridges like the .270, yet stands up very well in downrange performance with similar-weight bullets.
