.378 Weatherby Magnum
Place of origin
.22 Eargesplitten Loudenboomer is a cartridge for a rifle.
It was invented in the 1960s by P.O. Ackley to set a world record for firing bullets at over 5000 fps (1524 m/s). The round failed to reach the desired velocity, but reached 4600 fps with a 50 grain bullet and 105 grains of H570 powder. It is based on the .378 Weatherby Magnum cartridge case, necked down to .224 calibre.