.270 Winchester

From Wikipedia, the free encyclopedia
Jump to: navigation, search
.270 Winchester
100G115G130G150G.jpg
Left to Right 130-grain (8.4 g) - Hollow Point, 100-grain (6.5 g) FMJBT, 130-grain (8.4 g) Soft point, 160-grain (10 g) Lead round nose.
Type Rifle / Hunting
Place of origin United States
Production history
Designer Winchester
Designed 1923
Manufacturer Winchester
Produced 1925-Present
Specifications
Parent case .30-03 Springfield
Bullet diameter .277 in (7.0 mm)
Neck diameter .308 in (7.8 mm)
Shoulder diameter .441 in (11.2 mm)
Base diameter .470 in (11.9 mm)
Rim diameter .473 in (12.0 mm)
Case length 2.540 in (64.5 mm)
Overall length 3.340 in (84.8 mm)
Case capacity 67 gr H2O (4.3 cm3)
Rifling twist 1 in 10 in (250 mm)
Primer type Large rifle
Maximum pressure 65,000 psi (450 MPa)
Ballistic performance
Bullet weight/type Velocity Energy
90 gr (6 g) HP 3,603 ft/s (1,098 m/s) 2,595 ft·lbf (3,518 J)
130 gr (8 g) SP 3,060 ft/s (930 m/s) 2,702 ft·lbf (3,663 J)
140 gr (9 g) SP 2,916 ft/s (889 m/s) 2,644 ft·lbf (3,585 J)
150 gr (10 g) SP 2,850 ft/s (870 m/s) 2,706 ft·lbf (3,669 J)
130 gr (8 g) SST 3,200 ft/s (980 m/s) 2,955 ft·lbf (4,006 J)
Source(s): Hodgdon,[1] Hornady[2]

The .270 Winchester (or 6.9x64mm) was developed by Winchester Repeating Arms Company in 1923 and unveiled in 1925 as a chambering for their bolt-action Model 54.[3] The cartridge is based upon the .30-06.[4] When loaded with a bullet that expands rapidly or fragments in tissue, this cartridge delivers devastating terminal performance.[5][6][7]

The .270 Winchester became a very popular deer and elk cartridge due to the widespread praises of gunwriter Jack O'Connor who used the cartridge for 40 years and espoused its praise in the pages of Outdoor Life.[8][9] It drives an 8.4 grams (130 gr) bullet at approximately 960 m/s (3,140 ft/s), later reduced to 930 m/s (3,060 ft/s). The cartridge demonstrated high performance at the time of its introduction and was marketed as being suitable for big game shooting in the 370 to 910 metres (400 to 1,000 yd) range. Two additional bullet weights were soon introduced: a 6.5 grams (100 gr) hollow-point bullet for varmint shooting, and a 9.7 grams (150 gr) bullet for larger deer, elk and moose in big-game hunting.[3]

While not an immediate success, over the succeeding decades and especially in the post-World War II period, the .270 Winchester attained great popularity among gun owners and hunters, ranking it among the most popular and widely used cartridges worldwide. Internationally, firearms manufacturers now offer this chambering in all firearm varieties: bolt-actions, single-shots, lever-actions (such as Browning BLR), pump-actions (such as Remington 7600), autoloaders (such as Remington 7400) and even a few double rifles.[10]

Loads[edit]

Loads are commonly available from 6.5 to 10.4 grams (100 to 160 gr), sizes with 8.4-and-9.7-gram (130 and 150 gr) loads being by far the most popular. Handloaders have a larger range of options with the availability of bullets in a number of weights from 5.8 to 11.7 grams (90 to 180 gr). Common bullet weight recommendations for shooting different game are as follows:

  • 5.8–7.1 grams (90–110 gr) bullets: animals smaller than coyote.
  • 8.4 grams (130 gr) bullets: antelope or other animals up to the size of mule deer.
  • 9.1–10.4 grams (140–160 gr) bullets: deer, elk, moose and some larger animals.[1]

Recent introductions of low-drag bullets suited to the 270 Winchester such as the Nosler Accubond Long-Range and Matrix long range bullets are promoting renewed interest in the cartridge among long range hunters.

While it is true that a .270 Winchester case can be formed from a 30-06 Springfield case, the case length of a 30-06 is 63.3 millimetres (2.494 in) while the case length of a .270 is 64.5 millimetres (2.540 in), the same as a .30-03 Springfield. It is recommended that .270 Winchester brass be formed from .35 Whelen or .280 Remington cases.[11]

.270 Winchester cartridge

See also[edit]

References[edit]

  1. ^ a b .270 Win data from Hodgdon
  2. ^ Hornady Superformance commercial ammo specifications
  3. ^ a b The Complete Reloading Manual for the .270 Winchester, Loadbooks USA, Inc., 2004, pp.13,19
  4. ^ 30-03
  5. ^ Chamberlin FT, Gun Shot Wounds, in Handbook for Shooters and Reloaders, Vol. II, Ackley PO, ed., Plaza Publishing, Salt Lake City, Utah, 1966.
  6. ^ Scientific Evidence for Hydrostatic Shock
  7. ^ Shooter’s Bible, Robert F. Scott, p. 28
  8. ^ Barnes Reloading Manual Number 2 (1997)
  9. ^ Hornady Handbook of Cartridge Reloading, Fourth Edition (1996)
  10. ^ Speer Reloading Manual Number 12 (1994)
  11. ^ .270 Cartridge dimensions