Rifle · Wildcat
.22 Eargesplitten Loudenboomer
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.
- Caliber
- 0.224″ · 5.69 mm
- Introduced
- 1959
- Case
- Belted
- Parent
- .378 Weatherby Magnum
- Primary use
- target
- Status
- Active
- Introduced
- 1959
- Type
- Rifle
- Origin
- United States
- Inventor
- Bob Hutton / Guns & Ammo
- Manufacturer
- P.O. Ackley
- Standard
- Wildcat
- Status
- Active
- Availability
- Handload Only
- Case capacity
- 170 gr H₂O
- Twist (typical)
- 1:14
- Primer
- Large Rifle Magnum
- Case type
- Belted
- Max pressure
- 70,000 psi
- Eff. range
- 800 yd
- Recoil
- 8–12 ft·lb
Ballistics
Velocity only, no drag model: no published ballistic coefficient is on file for .22 Eargesplitten Loudenboomer, so this is the shape gravity alone gives the advertised velocity. Drag would steepen it. The tool below solves real loads through their published G1 or G7 model.
Open in Ballistic Compare- Parent case
- .378 Weatherby Magnum
Representative trajectory — modeled from a single velocity input (no published BC for this cartridge yet).
Dimensionscase measurements · scale drawing · size vs familiar rounds
Case dimensions — the scale drawing at the top of the page is built from these.
SAAMI · approximate| Measure | mm | in | ✓ |
|---|---|---|---|
| Bullet ⌀ | 5.69 | 0.224 | ~ |
| Neck ⌀ | — | — | |
| Shoulder ⌀ | 14.22 | 0.560 | ~ |
| Shoulder angle | — | — | |
| Base ⌀ | 14.78 | 0.582 | ~ |
| Rim ⌀ | 14.71 | 0.579 | ~ |
| Belt ⌀ | 15.33 | 0.604 | ~ |
| Rim thickness | 1.60 | 0.063 | ~ |
| Neck length | — | — | |
| Case length | 74.04 | 2.915 | ~ |
| Overall length | 91.44 | 3.600 | ~ |
Missing a dimension for .22 Eargesplitten Loudenboomer? Some case measurements aren't in a published SAAMI/CIP drawing yet. Have a factory or reamer print? Send it → — verified hard-to-find data earns a free Lindcott sticker.
Reloading costestimate cost per round vs factory
Estimate your cost per round and how it compares to factory. Inputs are yours — nothing is stored.
Cost estimate only — not load data. Charge weight is your input; follow published manuals for safe charges.
Lineage
Connected reference
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 occasionally built by experimenters and collectors.
FAQs
- What twist rate does .22 Eargesplitten Loudenboomer use?
- .22 Eargesplitten Loudenboomer typically uses a 1:14 twist rate.
- What bullet diameter is .22 Eargesplitten Loudenboomer?
- .22 Eargesplitten Loudenboomer uses a 0.224″ (5.69 mm) diameter bullet.
- Is .22 Eargesplitten Loudenboomer still in production?
- .22 Eargesplitten Loudenboomer is active; typical availability is handload only.
- What is .22 Eargesplitten Loudenboomer used for?
- .22 Eargesplitten Loudenboomer is primarily used for target.
- What is .22 Eargesplitten Loudenboomer based on?
- .22 Eargesplitten Loudenboomer is derived from the .378 Weatherby Magnum case.
Sources & provenance
Data & sources. Specs compiled from the Lindcott Armory reference; the trajectory is modeled (point-mass), not measured. See methodology. Spotted an error? Report it →