.270 Winchester

.270 Winchester

Description

The .270 Winchester is a rifle cartridge developed by Winchester Repeating Arms Company in 1923 and unveiled in 1925 as a chambering for their bolt-action Model 54. The cartridge is a necked-down .30-03 Springfield, which is the same length as the .280 Remington, both of which are longer than the .30-06 Springfield. Wikipedia
 
Bullet diameter.277 in (7.0 mm)
Rifling twist1 in 10 in (250 mm)
Case length2.540 in (64.5 mm)
Parent case.30-03 Springfield
Case capacity67 gr H2O (4.3 cm3)
Neck diameter.308 in (7.8 mm)
Base diameter.470 in (11.9 mm)