.378 Weatherby Magnum
The Weatherby Collection
After  production of his cartridges based on the .300 H&H case, Roy Weatherby produced an even
larger cartridge in 1953, based on the.416 Rigby Case.
The 378 Weatherby is a blown out 416 Rigby case to increase powder capacity, then necked down to
except .378  projectiles.
The cartridge has projectlies from 235 to 350 grain, and velocites  up to 3,200 Feet per Sec. to produce
up to 6,000 Foot Pounds of Energy per square inch. Yes,  6,000 Pounds !!!