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.The .240 Weatherby Magnum by Chuck Hawks
Design The .240 Weatherby 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 a similar length to 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.The .240 Weatherby Magnum by Chuck Hawks (subscription required)
Performance In terms of velocity, the .240 Weatherby Magnum was once the fastest commercially produced 6 mm cartridge. There were several faster wildcat rounds available, but the .240 Wby. Mag. outclassed the 6 mm Remington and the newer .243 WSSM by about .Compared: The .243 WSSM and .240 Wby. Mag. by Chuck Hawks (subscription required) However, the lightweight .243 WSSM 55gr Ballistic Silvertip now outpaces Weatherby's offerings according to some. Loading data from Western Powders puts the .240 Wby. Mag. at over with a 62 grain Barnes bullet.
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 heavier bullets the .240 Wby. Mag. makes for a good deer hunting cartridge, but it does tend to require a long (>.) barrel in order to achieve peak performance.
+Performance for 100 grain bullet from utilizing a factory 26" test barrel and a Nosler Partition bullet) Muzzle 100 yd 200 yd 300 yd 400 yd 500 ydTrajectory 2.8 3.5 0 -8.4 -22.9Energy (ft·lbf)2576 2183 1844 1550 1294 1073Velocity (ft/s)3406 3136 2882 2642 2415 2199
+.240 Weatherby Performance Comparison Cartridge Bullet weight Muzzle velocity Muzzle energy .240 Weatherby Magnum .240 Apex .242 Rimless Nitro Express .243 Winchester .243 Winchester Super Short Magnum .244 H&H Magnum .246 Purdey 6 mm Lee Navy 6 mm Remington
See also List of rifle cartridges Table of handgun and rifle cartridges
References
at Steves Pages mm)/240%20Weatherby%20Magnum%20page%20209.pdf .240 Wby data at Accurate Powder
External links Weatherby Web Site