The projectile is a .277"... the case is short... You could almost call it a 270 short.. like a 22 short 
http://en.wikipedia.org/wiki/6.8_mm_Remington_SPC
another thing... there are 2 different chambers for 6.8spc..gotta hope you get the right one.
http://en.wikipedia.org/wiki/6.8_mm_Remington_SPC
another thing... there are 2 different chambers for 6.8spc..gotta hope you get the right one.