.270 Winchester

From Wikipedia, the free encyclopedia

.270 Winchester
Left to Right 100-grain (6.5 g) - Hollow Point, 115-grain (7.5 g) FMJBT, 130-grain (8.4 g) Soft point, 150-grain (9.7 g) round nose.
Type	Rifle / Hunting
Place of origin	United States
Production history
Designer	Winchester
Designed	1923
Manufacturer	Winchester
Produced	1925-Present
Specifications
Parent case	.30-06
Bullet diameter	.277 in (7.0 mm)
Neck diameter	.278 in (7.1 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)
Rifling twist	1-10
Primer type	Large rifle
Ballistic performance
Bullet weight/type	Velocity	Energy
90 gr (5.8 g) HP	3,603 ft/s (1,098 m/s)	2,595 ft·lbf (3,518 J)
130 gr (8.4 g) SP	3,085 ft/s (940 m/s)	2,748 ft·lbf (3,726 J)
140 gr (9.1 g) SP	2,916 ft/s (889 m/s)	2,644 ft·lbf (3,585 J)
150 gr (9.7 g) SP	2,850 ft/s (870 m/s)	2,706 ft·lbf (3,669 J)
Source: Hodgdon ^[1]

The .270 Winchester was developed by Winchester Repeating Arms Company in 1923 and unveiled in 1925 as a chambering for their bolt action Model 54^[2]. The cartridge is based upon the .30-06 Springfield, and the case is slightly longer due to the necking down process.

Driving a 130-grain (8.4 g) bullet at approximately 3140 ft/s (957 m/s), (later reduced to 3060 ft/s (933 m/s)) the cartridge demonstrated high performance at the time of its introduction and was marketed as being suitable for long range shooting on most big game. Two additional bullet weights were soon introduced: a 100-grain (6.5 g) hollow point bullet for Varmint shooting, and a 150-grain (9.7 g) bullet for larger deer, elk and moose in North American hunting^[2]. While not an immediate success, over the succeeding decades and especially in the post WW2 period, the .270 Winchester has 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.

1 Overview
2 Loads
3 See also
4 References

[edit] Overview

The .270 Winchester offers superb accuracy in good bolt action rifles, an extremely flat trajectory, and good long range punch, all at a level of recoil tolerable to most shooters. The .270 has been used at one point or another to take all North American large game, but is probably not a good choice of caliber for large dangerous game such as brown or polar bears. Although some argue that a 110-grain (7.1 g) bullet should only be used on smaller game, the velocity achieved when using a 110-grain (7.1 g) bullet will take a white tail. Jack O'Connor, writer for and then Shooting Editor of Outdoor Life magazine from 1939 to 1972, strongly promoted the .270 Winchester for many hunting applications in North America and Africa undoubtedly increasing its appeal to hunters and gun enthusiasts.^[3] O'Connor remains the most passionate and influential single advocate in the cartridge's long history.

Many non-American riflemen, and ballisticians in general, have been mildly surprised by the massive success of the .270 with its "oddball" .277in bullet, and feel that the .280 Remington/7mm Express Remington, firing a "true" 7mm/.284in bullet from what is effectively a similarly necked-down .30-'06 case, could have cornered a similarly large market, had it been released in time. But the US market may have perceived the 7 mm diameter bullet as essentially European in origin and pedigree, and thus "not made here", while the .270 was aggressively and most successfully marketed as a new, all-American caliber. It has never made much headway as an African plains game caliber, with hunters preferring the parent (and even more internationally successful) .30-06 cartridge with its wider choice of bullets, especially in the heavier weights.^{[citation needed]} United Kingdom red deer stalkers have been sharply divided over the .270. Some swear by it for its flat trajectory and long-range punch, while others swear at it for its noise and harsh recoil.^{[citation needed]} It is undoubtedly an abrupt-shooting cartridge by comparison with the UK's long-time benchmarks, the 7x57 Mauser/.275 Rigby and 6.5 mm × 54 Mannlicher-Schönauer, or the newer 7mm-08 Remington, although it has less recoil than the .30-06. UK market interest in the .270 has, however, revived somewhat since the 1990s with the widespread police approval of sound moderators (a.k.a. suppressors) for civilian-owned centerfire rifles, since a moderator noticeably attenuates the .270's loud report. The relatively strong recoil of this cartridge can be mitigated with the addition of a reliable recoil pad on the rifle buttstock.

The .270 has never been a military caliber. Additionally, while Sierra Bullets does manufacture a 135-grain (8.7 g) MatchKing bullet for target applications, it is rarely found in benchrest or other target competitions. Even so, today the .270 one of the 5 most popular rifle calibers in the world following closely behind the .30-06 Springfield in terms of firearms and ammunition sold ^[4].

[edit] Loads

Factory bullets are commonly available in 100, 130, 140, 150 and 160-grain (10 g) sizes with 130 and 150-grain (9.7 g) 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 90 to 180 grains (12 g). Common bullet weight recommendations for shooting different game are as follows:

90-110 grain bullets: animals smaller than antelope.
130 grain bullets: antelope or other animals up to the size of mule deer.
140-180 grain bullets: deer, elk, moose and anything larger.^[1]

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 2.494 inches (63.3 mm) while the case length of a .270 is 2.540 inches (64.5 mm). ^[5].