Originally Posted by
Hermitage
There’s no denying that the 270 Win and 6.5 Creedmoor have impressive ballistics. The 270 is the obvious choice when kinetic energy is needed, as it fires similarly weighted bullets to the 6.5 CM at higher velocities.
This begs the question as to why the 6.5 CM is so popular? If the 270 has more case capacity, why then do we see the firing line at F-Class competitions flooded with 6.5 Creedmoor?... The answer lies in the barrel and bullet selection.
The 6.5 Creedmoor was designed to shoot long, high B.C. bullets. Long, heavy bullets require a faster twist rate to stabilize properly. Therefore, a 1:8 twist barrel was standardized for the calibre.
On the other hand, we need to remember what the 270 was designed to do; which is provide a flatter shooting alternative to its parent case, the 30-06 Springfield. Back in the 1920’s, it’s highly unlikely that ballistic coefficients were weighing heavily on the minds of rifle makers.
Back then, velocity was king and the 130 grain Spitzer fired by the 270 Win quickly became known as a flat shooting bullet. Therefore, the manufacturers standardized the 1:10 twist rate for the 270, which is good for bullets up to 150 grains, but not much heavier than that (unless you use your rounded low BC 170 grainers) This gives the 6.5 Creedmoor a clear advantage in terms of bullet selection thanks to its faster twist rate.