.22 Spitfire

The .22 Spitfire (also known as 5.7mm Johnson or MMJ 5.7mm Johnson[1]) is an American rifle cartridge.

.22 Spitfire
5.7mm Johnson Spitfire.jpg
.22 Spitfire with FN 5.7×28mm and .30 Carbine cartridges
Place of originUSA
Production history
DesignerMelvin M. Johnson
ManufacturerJohnson Guns Inc.
Parent case.30 Carbine
Bullet diameter.224 in (5.7 mm)
Neck diameter.253 in (6.4 mm)
Shoulder diameter.332 in (8.4 mm)
Base diameter.353 in (9.0 mm)
Rim diameter.356 in (9.0 mm)
Case length1.29 in (33 mm)
Overall length1.65 in (42 mm)
Rifling twist1:14
Primer typeBoxer small rifle
Ballistic performance
Bullet mass/type Velocity Energy
40 gr (3 g) 2,850 ft/s (870 m/s) 720 ft⋅lbf (980 J)
40 gr (3 g) 3,000 ft/s (910 m/s) 795 ft⋅lbf (1,078 J)
50 gr (3 g) 2,700 ft/s (820 m/s) 810 ft⋅lbf (1,100 J)
Source(s): Barnes & Amber

Designed by Melvin M. Johnson of Johnson Guns Inc. for their conversion of the M1 carbine,[2] this wildcat[3] was introduced in 1963. It was based on the .30 Carbine, necked-down to .22 (5.7mm) to take a .224 bullet.[3][4]

It is suitable for rabbits, coyotes, or other varmints,[3] and has potential as a military round.[3]

See alsoEdit


  1. ^ "Reloading Quick Reference - Reloading". Cheaperthandirt.com. Archived from the original on 2012-03-14. Retrieved 2012-05-22.
  2. ^ Barnes, Frank C., ed. by John T. Amber. Cartridges of the World (Northfield, IL: DBI Books, 1972), p.127.
  3. ^ a b c d Barnes and Amber, p.127.
  4. ^ Woodard, W. Todd (2016). Cartridges of the World: A Complete and Illustrated Reference for Over 1500 Cartridges. Gun Digest Books. ISBN 978-1-4402-4648-7.


  • Barnes, Frank C., ed. by John T. Amber. "MMJ-5.7mm", in Cartridges of the World, pp. 127 & 143. Northfield, IL: DBI Books, 1972. ISBN 0-695-80326-3.