.240 Weatherby Magnum

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.240 Weatherby Magnum

Type	Rifle
Place of origin	USA
Production history
Designer	Roy Weatherby
Designed	1968
Manufacturer	Weatherby
Specifications
Bullet diameter	.243 in (6.2 mm)
Neck diameter	.272 in (6.9 mm)
Shoulder diameter	.429 in (10.9 mm)
Base diameter	.453 in (11.5 mm)
Rim diameter	.472 in (12.0 mm)
Case length	2.496 in (63.4 mm)
Overall length	3.100 in (78.7 mm)
Rifling twist	1-10"
Primer type	Large rifle
Ballistic performance
Bullet weight/type	Velocity	Energy
60 gr (3.9 g) HP	3,817 ft/s (1,163 m/s)	1,942 ft·lbf (2,633 J)
75 gr (4.9 g) HP	3,555 ft/s (1,084 m/s)	2,105 ft·lbf (2,854 J)
80 gr (5.2 g) SP	3,514 ft/s (1,071 m/s)	2,194 ft·lbf (2,975 J)
90 gr (5.8 g) SP	3,394 ft/s (1,034 m/s)	2,303 ft·lbf (3,122 J)
100 gr (6.5 g) HP	3,202 ft/s (976 m/s)	2,277 ft·lbf (3,087 J)
Source: Hodgdon ^[1]

The .240 Weatherby Magnum was developed in 1968 by Roy Weatherby. In the development of his own .240in/6 mm cartridge, Weatherby was significantly influenced by both the success and the limitations of the .244 H&H Magnum cartridge devised in England by his friend and colleague David Lloyd. It was the last cartridge to be designed by Roy Weatherby.^[2]

1 Design
2 Performance
3 See also
4 References
5 External links

[edit] Design

The .240 Wby. Mag. is a proprietary cartridge used only in Weatherby rifles. This particular Weatherby case is unique, other than shape, it isn't physically based on other Weatherby cases, having the same rim diameter and similar length as the .30-06. It utilizes the traditional Weatherby rounded double shoulder and a belted case with a length of 2.496in, significantly shorter than the 2.8in case of the .244 H&H Mag. ^[3]

[edit] Performance

In terms of velocity, the .240 Weatherby is the fastest commercially produced 6 mm cartridge. There are of course several faster wildcat rounds available, but the .240 Wby outclasses the 6 mm Remington and the newer .243 WSSM by about 150 ft/s (46 m/s). ^[4] While favoured by some varmint hunters, the .240 Wby. Mag. is not much liked by some reloaders because the case cannot be formed out of any other brass; one either has to buy Weatherby ammunition or reload used Weatherby cases which tend to be more expensive than those for more common cartridges. With the heavier bullets the .240 Wby. Mag. makes for a good deer hunting cartridge, but it does tend to require a long (>23in.) barrel in order to achieve peak performance.