A shortened .222 Remington designed for the XP-100 bolt-action pistol. Achieved 2,650 fps from a 10-inch pistol barrel — proving centerfire rifle cartridges could work in handguns.
Type: Pistol
Introduced: 1963, United States
Parent case: .222 Remington
Standardization: SAAMI
Bullet diameter: 0.224" (5.69 mm)
Case length: 1.4" (35.56 mm)
Overall length: 1.82" (46.23 mm)
Max pressure: 52,000 PSI
Rim type: Rimless
Primer: Small Rifle
Typical twist rate: 1:14
Muzzle velocity: 2400–2800 fps
Muzzle energy: 510–870 ft-lbs
Effective range: 200 yd
Common bullet weights: 40, 50, 52 gr
Primary use: Competition, Varmint
Production status: Active
Also known as: .221 Fireball
History: Remington created it specifically for the XP-100 bolt-action handgun in 1963. The XP-100 was the world's first modern bolt-action centerfire pistol. The Fireball's short case was optimized for 10-14" barrels. It later became a parent case for wildcats and inspired the .17 Fireball.
Notable firearms: Remington XP-100, Savage Striker, Thompson/Center Contender
Similar cartridges: .222 Remington, .17 Hornet