Parker Ackley's famous experiment in maximum velocity — the .378 Weatherby Magnum case necked to .224, reportedly achieving 5,000+ fps with 50-grain bullets. Named by Ackley himself with characteristic humor. An extreme wildcat of purely academic interest; barrel life is measured in hundreds of rounds.
Type: Rifle
Introduced: 1959, United States
Parent case: .378 Weatherby Magnum
Standardization: Wildcat
Bullet diameter: 0.224" (5.69 mm)
Max pressure: 70,000 PSI
Rim type: Belted
Primer: Large Rifle Magnum
Typical twist rate: 1:14
Muzzle velocity: 4600–5100 fps
Muzzle energy: 2350–3000 ft-lbs
Effective range: 800 yd
Common bullet weights: 50, 52 gr
Primary use: target
Production status: Active
Also known as: Eargesplitten Loudenboomer · .22 EL · EL
History: Parker Ackley built this cartridge in 1959 as a deliberate attempt to produce the highest possible muzzle velocity from a sporting rifle. The name is a mock-Germanic compound word roughly translating to "ear-splitting loud boomer." Though never practical, it demonstrated the theoretical limits of small-bore velocity and became one of the most famous wildcats in American firearms history. Still…