270 Weatherby Magnum Ballistics

270 Weatherby Magnum History

The 270 Weatherby Magnum was introduced to the shooting public in 1945 by Roy Weatherby. The cartridge case itself is a shortened 300 H&H; Magnum case with the body blown out and necked down to accept a .27 caliber bullet.

The 270 Weatherby Magnum is an excellent, accurate, and flat shooting cartridge that is capable of taking any big game in the lower 48 states and is one of the more powerful 27 caliber cartridges, when loaded with 130 grain bullets at 3300 feet per second it is a very adequate round for deer at 500 yards and when loaded with 150 grain bullets at 3200 feet per second it is a very adequate round for elk at 400 yards.

The 270 Weatherby Magnum will recoil considerably with 150 grain bullets but if loaded down with 110 grain varmint bullets to a velocity of around 3,400 feet per second the recoil is quite tolerable.

270 Weatherby Magnum Barrel Specifications

Common Barrel Twist Rate – 1/10 – 1/12
Bore Groove Diameter – .277″

270 Weatherby Magnum Reloading Specifications

Bullet Diameter – .277″
Maximum Case Length – 2.550″
Trimmed Case Length – 2.540″
Primer Size – Large Rifle

270 Weatherby Magnum Loading Data Hints

The 270 Weatherby Magnum will come to life with slower burning powders IMR 4350 and 4831, when using 150 grain weight bullets the full devastating power potential of this cartridge will be realized.

The following is a down range trajectory chart for the 270 Weatherby Magnum cartridge with the scope mounted 1.5 inches above the bore center line. If you were using this load, its effective hunting bullet energy range with well placed shots on:

Varmint or Predator size game such as Bobcat, Cougar, and Coyote.
Deer size game such as Antelope, Blacktail, Hogs, Javelina, Mule, and Whitetail.
Elk size game, such as Caribou, Black Bear and Sheep.
Moose size game, such as Brown Bear.

Bullet diameter .264″
Bullet weight 140 grains
Bullet ballistic coefficient .441
Bullet velocity 3,100 feet per second