.308 Winchester vs .300 WSM
A to-scale size comparison of the .308 Winchester and the .300 WSM, drawn from SAAMI and C.I.P. cartridge dimensions and aligned at the case head.
.308 Winchester (left) beside .300 WSM (right), shown at the same scale.
The .308 Winchester has an overall length of about 2.81″ with a 0.309″ bullet. The .300 WSM runs about 2.86″ on a 0.309″ bullet. The two are close in overall length. See the full reference for each: .308 Winchester and .300 WSM.