.378 Weatherby Magnum

colspan="3" style="background: lightsteelblue; text-align: center; vertical-align: middle;"

| .378 Weatherby Magnum colspan="3" style="text-align: center; font-size: 90%; border-bottom: 1px solid #aaa; line-height: 1.25em;"

| File:Munit01.jpg
Type Centerfire/Rifle Place of origin South Gate, California colspan="3" style="background: lightsteelblue; text-align: center; vertical-align: middle;"

| Production history Designer Roy Weatherby Designed ca1950 Manufacturer Weatherby Produced 1953-Present colspan="3" style="background: lightsteelblue; text-align: center; vertical-align: middle;"

| Specifications Case type Belted Bullet diameter .375 in (

 mm

)

Neck diameter .399 in (

 mm

)

Shoulder diameter .560 in (

 mm

)

Base diameter .582 in (

 mm

)

Rim diameter .603 in (

 mm

)

Rim thickness .059 in (

 mm

)

Case length 2.913 in (

 mm

)

Overall length 3.65 in (

 mm

)

Rifling twist 1 in 12 Primer type Large rifle magnum colspan="3" style="background: lightsteelblue; text-align: center; vertical-align: middle;"

| Ballistic performance Bullet weight/type Velocity Energy style="vertical-align:middle; border-bottom: 1px dotted #aaa;

" | 300 gr (

 g)

Full Metal Jacket||style="border-bottom: 1px dotted #aaa;

"|2,925 ft/s (

 m/s)

||style="border-bottom: 1px dotted #aaa;

"|5,699 ft·lbf (

 J)

style="vertical-align:middle; border-bottom: 1px dotted #aaa;

" | 300 gr (

 g)

Round nose||style="border-bottom: 1px dotted #aaa;

"|2,925 ft/s (

 m/s)

||style="border-bottom: 1px dotted #aaa;

"|5,699 ft·lbf (

 J)

style="vertical-align:middle; border-bottom: 1px dotted #aaa;

" | 270 gr (

 g)

Truncated solid||style="border-bottom: 1px dotted #aaa;

"|3,060 ft/s (

 m/s)

||style="border-bottom: 1px dotted #aaa;

"|5,615 ft·lbf (

 J)

style="vertical-align:middle; border-bottom: 1px dotted #aaa;

" | 270 gr (

 g)

Pointed soft point||style="border-bottom: 1px dotted #aaa;

"|3,180 ft/s (

 m/s)

||style="border-bottom: 1px dotted #aaa;

"|6,062 ft·lbf (

 J)

style="vertical-align:middle; border-bottom: 1px dotted #aaa;

" | 260 gr (

 g)

Partitiion Type||style="border-bottom: 1px dotted #aaa;

"|3,140 ft/s (

 m/s)

||style="border-bottom: 1px dotted #aaa;

"|5,743 ft·lbf (

 J)

Test barrel length: 26 in (66 cm)
Source: Weatherby / Nosler

The .378 Weatherby Magnum was designed by Roy Weatherby in the early 1950s. The .378 Weatherby Magnum is an original design with no parent case. The belted magnum cartridge was inspired by the capacity of the .416 Rigby case and headspacing of the .375 H&H Magnum belted case. The Magnum rifle primer, named the 215 primer was developed by Federal Cartridge Company for the .378 Weatherby Magnum cartridge. The .378 Weatherby Magnum cartridge can hold upwards of 7.13 g (110 gr) of powder. The 378 Weatherby Magnum cartridge also has the double radius shoulder design found on the first and smaller proprietary line of Weatherby magnum cartridges. The .378 Weatherby Magnum cartridge was put into production 1953 to replace the .375 Weatherby Magnum.

The motivation behind the development of the .378 Weatherby Magnum came from the disappointing performance gains of the improved, .375 Weatherby Magnum over its parent case, the .375 H&H Magnum. Roy Weatherby in 1953 shot an African Elephant with one bullet while on safari. However in using this event as a marketing tool, it was revealed that some African countries have a minimum 12.43 mm (.40 caliber) bullet size for hunting dangerous game. The Weatherby company responded by necking up the .378 Weatherby Magnum to 11.63 mm (.458 caliber) and called the new cartridge, the .460 Weatherby Magnum; introduced in 1958.

The .378 Weatherby Magnum is considered a Safari grade cartridge designed to hunt large African game animals. The .378 Weatherby Magnum is appropriate for taking all African game animals from large African antelopes, Nile crocodile (Crocodylus niloticus), Hippopotamus (Hippopotamus amphibius), to the Big Five game. Some hunters on the North American continent employ the .378 Weatherby Magnum for use when hunting American Elk (cervas canadensis), Brown Bears (Ursus arctos) and Polar Bears (Ursus maritimus).

The .378 Weatherby Magnum will generate considerable free recoil; an average of 104 J (77 ft·lbf) from a 4.1 kg (9 lb) rifle. This is in comparison to an average free recoil of 27 J (20 ft · lb_f) from a rifle chambered for .30-06 Springfield. It is written that the .378 Weatherby Magnum will create a greater felt recoil than other cartridges, but this concept is at odds with the laws of physics. This misconception has likely done a lot to reduce the popularity of this caliber. This includes two of its off-spring; the .416 Weatherby Magnum and .460 Weatherby Magnum.

The .378 Weatherby Magnum has been responsible for numerous wildcat cartridges, being necked-down to the .22 Eargesplitten Loudenboomer (5.56 mm) and being necked-up .500 A-Square (12.7 mm). Some of the .378 Weatherby Magnum wildcat cartridges are shortened versions, like the .30-378 Arch (7.62 mm) and the .460 Short A-Square (11.63 mm). Some of the .378 Weatherby Magnum wildcat cartridges have gone on to be part of the Weatherby line: .30-378 Weatherby Magnum; .338-378 Weatherby Magnum; .416 Weatherby Magnum and .460 Weatherby Magnum.

Categories

Cartridge:rifles