Hi camp_13,
The 6.5 Remington Magnum has the same case dimensions as the .350 Remington Magnum......except necked down. As far as compared too......think 7mm Remington Magnum.....with the case shortened to allow it to work through a short action. For a little more general info......go to:
http://www.chuckhawks.com/6-5mm_rifle_cartridges.htm
http://www.reloadersnest.com/frontpa...?CaliberID=207
Hope this helps!
Dave