.221 Remington Fireball

Cartridge Data Published On: December 20, 2014 at 11:36 pm by Bullet-Blog and last updated on February 12, 2015 at 11:24 am


5.56×35.4mm US, .221 Remington, .221 Fire-Ball


The .221 Remington Fireball (AKA: 5.56×35.4mm US, .221 Remington, .221 Fire-Ball) is a Center Fire cartridge with a Bullet Diameter of 0.224 in” (5.69mm) that is primarily used in Pistols and Rifles. The .221 Remington Fireball originated in The United States in 1963. The .221 Remington Fireball also has a case length of 1.4 in” (35.56mm) and an overall length of 1.82 in” (46.23mm).


The .221 Remington Fireball is a shortened version of the .222 Remington and was created originally for use in the XP-100 Pistol, an experimental bolt action pistol created in the 1960s by the Remington Arms Company. The .221 Remington Fireball is capable of reaching well over 3000fps with a 40 grain projectile, with energies topping an amazing 1000 ft/lbs, all from a pistol.

The .221 Remington Fireball has been attributed to many off shoots and various Wildcat Cartridges. Because of its case design, the .221 Remington Fireball is capable of high pressures and is given a pressure rating of 52,000 CUP by SAAMI, topping its counterpart the .222 Remington and creating some of the highest velocities capable in a pistol cartridge.

Associated Firearms

Remington XP-100, Remington 700, CZ 527

Cartridge Details

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  • 1963
  • The United States
  • Rimless,Bottleneck
  • Pistols
  • 0.224 in” (5.69mm)
  • 0.253 in” (6.43mm)
  • 0.361 in” (9.17mm)
  • 0.376 in” (9.55mm)
  • 0.378 in” (9.6mm)
  • 0.05 in” (1.14mm)
  • 1.4 in” (35.56mm)
  • 1.82 in” (46.23mm)
  • Center Fire (Small Rifle)
  • 320 MPa (46412 psi)
  • ~416 MPa (60336 psi)

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