.270 Weatherby Magnum

.270 Weatherby Magnum
.270 Weatherby 2nd from left
Type	Rifle / Hunting
Place of origin	USA
Production history
Designer	Roy Weatherby
Designed	1943
Manufacturer	Weatherby
Specifications
Parent case	.300 H&H Magnum
Case type	Belted, bottleneck
Bullet diameter	.277 in (7.0 mm)
Neck diameter	.303 in (7.7 mm)
Shoulder diameter	.492 in (12.5 mm)
Base diameter	.512 in (13.0 mm)
Rim diameter	.531 in (13.5 mm)
Rim thickness	.220 in (5.6 mm)
Case length	2.55 in (65 mm)
Overall length	3.25 in (83 mm)
Rifling twist	1-10"
Primer type	Large rifle magnum
Ballistic performance
Bullet weight/type	Velocity	Energy
110 gr (7.1 g) HP	3,528 ft/s (1,075 m/s)	3,041 ft·lbf (4,123 J)
130 gr (8.4 g) X	3,338 ft/s (1,017 m/s)	3,217 ft·lbf (4,362 J)
140 gr (9.1 g) BT	3,242 ft/s (988 m/s)	3,268 ft·lbf (4,431 J)
150 gr (9.7 g) SBT	3,161 ft/s (963 m/s)	3,329 ft·lbf (4,514 J)
Test barrel length: 26" Source: Accurate Powder [1]

The .270 Weatherby Magnum was the first belted magnum based on the .300 H&H Magnum to be developed by Roy Weatherby. It has the characteristic double-radius shoulders and is necked down to accommodate the .277in bullets. Being a proprietary cartridge, the .270 Weatherby has no official SAAMI maximum pressure limit. Weatherby factory ammunition is loaded to 71,000 PSI.^[1] The first Weatherby cartridge to be used in Africa was the .270 Weatherby on a jackal on June 8, 1948. ^[2]

[edit] Performance

Given its higher pressure and larger case which holds more powder than the .270 Winchester, the .270 Weatherby has about 200 ft/s faster performance with any particular bullet weight. This performance comes at the cost of more recoil and barrel heat. In addition, a long barrel is necessary to take advantage of extra powder to gain maximum velocity. The cartridge is excellent at long-range hunting, but is not well suited to high-volume shooting such as varmint hunting.^[3]

For those handloading their own cartridges, this is an easy round to load. It does best with full-power loads and is not well-suited for reduced loads. ^[3][4] Ed Weatherby, son of Roy Weatherby says that the .270 Weatherby is his favorite caliber. As he puts it, there just isn't a better long-range deer caliber. He goes on to mention that it is also quite effective for elk, and pronghorn.^[2]

[edit] See also

• List of rifle cartridges
• 7 mm caliber

[edit] References

1. ^ ^{a b} .270 Weatherby data from Accurate Powder
2. ^ ^{a b} Nosler, Inc. (2002). [www.nosler.com Nosler Reloading Guide] (5th Edition ed.). Bend, OR, USA: Nosler, Inc.. pp. 219-224. www.nosler.com. 
3. ^ ^{a b} Barnes, Frank C. (2006) [1965]. Skinner, Stan. ed.. Cartridges of the World (11th Edition ed.). Iola, WI, USA: Gun Digest Books. pp. 43. ISBN 0-89689-297-2. 
4. ^ Ackley, P.O. (1927) [1962]. Handbook for Shooters & Reloaders. vol I (12th Printing ed.). Salt Lake City, Utah: Plaza Publishing. pp. 384,385. ISBN 978-9992948811.