340 Weatherby Magnum History and General Information.  The 340 Weatherby Magnum was developed by necking up Weatherby's already well established 300 Weatherby Magnum to a bullet diameter of .338 inches. This filled the Weatherby cartridge gap between their 300 Magnum and 375 Magnum. This cartridge went into mass production in 1963.  The 340 Weatherby Magnum is very powerful, loaded with a 225 grain bullet and the velocity topping out at 3,000 feet per second it will deliver a little over 1 ton (2,000 Foot Pounds) of energy at the 500 yard mark.  This is clearly a powerful cartridge. It is however a very flat shooting cartridge and one that has its place in mountain hunting in north america and in Alaska for large moose and bear.  The 340 Weatherby Magnum when loaded with 225 grain bullets produces recoil that is very substantial and this cartridge is only recommended to those who have shot other big bore caliber Magnum rifles and found that they could deal with severe recoil.  Barrel porting for this this cartridge is a real good idea.   340 Weatherby Magnum Barrel Specifications. Common Barrel Twist Rate - 1/10 Bore Groove Diameter - .338"   340 Weatherby Magnum Reloading Specifications. Bullet Diameter - .338" Maximum Case Length - 2.825" Trimmed Case Length - 2.815" Primer Size - Large Rifle   340 Weatherby Magnum Loading Data Hints.  The 340 Weatherby Magnum when loaded with hornady 225 grain bullets backed with a charge of i.m.r. 7828 powder delivers superior accuracy and packs enough energy for anything in all of north american hunting and most african game. 340 Weatherby Magnum Reloading Data. Hodgdon Reloading Data Center.   340 Weatherby Magnum Trajectory and Hunting Applications.  This is a down range trajectory chart for the 340 Weatherby Magnum cartridge with the scope mounted 1.5 inches above the bore center line plus if you were using this load, its effective hunting bullet energy range with well placed shots on, Varmint / Predator size game, such as Bobcat, Cougar, Coyote. Deer size game, such as Antelope, Blacktail, Hogs, Javelina, Mule, Whitetail. Elk size game, such as Caribou, Black Bear, Sheep. Moose size game, such as Brown Bear. Bullet diameter .338" Bullet weight 225 grains Bullet ballistic coeffecient .452 Bullet velocity 3,000 feet per second Range 100 yds. 200 yds. 300 yds. 400 yds. 500 yds. + + 1.6 0 - 6.9 - 20.3 - 41.3 3874 3320 2834 2409 2040  Varmint + + + + + +  Deer + + + + + +  Elk + + + + + +  Moose + + + + + - Copyright 2001 - 2010