30 Rem. case, the 6.8 SPC uses a 0.277"-diameter bullet that doubles the weight of the most popular bullets in the .223 Rem., but with only a moderate reduction in velocity from a short barrel.

223 Rem.) some 10 years later ... it delivers excellent performance. Part of the 6.8 SPC’s development was ballistic testing in standard ordnance gelatin. During this testing, the 6.8 mm ...