6mm Creedmoor vs .30-378 Weatherby
A to-scale size comparison of the 6mm Creedmoor and the .30-378 Weatherby, drawn from SAAMI and C.I.P. cartridge dimensions and aligned at the case head.
6mm Creedmoor (left) beside .30-378 Weatherby (right), shown at the same scale.
The 6mm Creedmoor has an overall length of about 2.80″ with a 0.243″ bullet. The .30-378 Weatherby runs about 3.75″ on a 0.308″ bullet. That makes the .30-378 Weatherby about 1.3x the overall length of the 6mm Creedmoor. See the full reference for each: 6mm Creedmoor and .30-378 Weatherby.