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**44 AMP** · July 13, 2019, 05:27 PM

The 5.7mm MMJ /Johnson Spitfire was introduced in 1963 for Johinson Guns modified M1 Carbines. based on the .30 carbine case necked down to .22 cal.

Reported velocity is 3000fps with a 40gr and 2700fps with a 50 gr bullet.
A wildcat round, the rifles were not a long lived commercial success.

July 13, 2019, 05:27 PM	#22
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,803	The 5.7mm MMJ /Johnson Spitfire was introduced in 1963 for Johinson Guns modified M1 Carbines. based on the .30 carbine case necked down to .22 cal. Reported velocity is 3000fps with a 40gr and 2700fps with a 50 gr bullet. A wildcat round, the rifles were not a long lived commercial success. __________________ All else being equal (and it almost never is) bigger bullets tend to work better.