Guns & Calibers from the past; Johnson MMJ 5.7mm Spitfire!

The first thing we need to know is the creator of this caliber, "MMJ" Melvin Maynard Johnson Jr. He was commissioned into the Marine Corps Reserve in 1933 as a Second Lieutenant and completed Harvard Law School in 1934. Johnson designed the M1941 Johnson rifle, the Johnson Light Machine Gun and the M1947 Johnson auto carbine. So clearly he was a man that understood the dynamics of weapons design.

In 1963 he founded his Johnson Arms, Inc business. Developing models that utilized the M1 Carbine chambered in his creation the Johnson MMJ 5.7mm Spitfire. He also offered barrels chambered in that caliber for converting any M1 Carbine by replacing the barrel with modifications of the feed ramp. Johnson advertised this new smaller caliber and the modified carbine as a survival rifle being light, fast handling with a low recoil.

So what was this new caliber all about? The cartridge is based on the .30 Carbine that was necked-down to .22 caliber. With that the Johnson MMJ 5.7mm Spitfire A.K.A. 22 Spitfire, 5.7mm Johnson or 5.7mm MMJ American wildcat cartridge was born.

Today these Carbines are seldom encountered. However, years ago I was very fortunate to stumble onto one. A young fellow had inherited one from an Uncle and was walking around the Rickreall winter gun show with it. When I first laid eyes on it, it just appeared to be a custom stocked M1 Carbine. Several people had looked at it but handed it back after he had told them about the caliber, 5.7mm Spitfire. Well, obviously that made me smile and it went home with me.

Factory ammunition was once manufactured for the Carbine but has long disappeared from the market. However at the last Rickreall winter show I was able to purchase a box from an old friend.

Pictured below is the custom Mannlicher thumbhole stocked Carbine and the box of ammunition. The action has been anodized and I have no idea who completed the work. But I find the Mannlicher style stock to be very handsome and I'm just waiting for some nice weather to take it out for a test drive.


If you happen to have any ammunition or dies laying around for this and want to sell them, please contact me.

spitfire 2.jpg

spitfire 4.jpg spitfire 3.jpg spitfire 1.jpg
Last Edited:
Beautiful little rifle! I'm sure curious about the ballistics. Could you have custom dies made and neck down. 30 carbine brass?

There are dies out there, just one of those wait and get lucky times.
Bullet weight/typeVelocityEnergy
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)
Given the ballistics of this cartridge, I am even more convinced that FN could have done better with the ballistics for the 5.7x28.

I know that they have a straight walled body on the cartridge (not including the neck) and that this makes extraction an issue, but the rotary mag helps with feeding (no slope/ramp necessary as the cartridge is fed straight in), but they could do a roller block or radial delayed like CMMG does, and have a cartridge that has more powder room and better ballistics, plus a longer neck (to hold the projectile better). Even the .22 TCM has better ballistics.

5.7x28 vs .22 TCM:
5.7, 22TCM - all are just now recapturing what Col. Johnson conceived of decades ago.
Q: Are you sure that receiver is anopdized? That process, when used on steel, causes pitting and corrosion beneath the surface.
Q: Might it be epoxy, which was a new technology back then?
Q: Is tht a GI receiver, or commercial (Universal/Plainfield/Iver Johnson) perhaps?

Upcoming Events

Latest Resource Reviews

New Classified Ads

Back Top