before the 5.56mm NATO cartridge

[RCS]

I got these early cartridges long time ago, do not how rare they are ? but really have not seen many examples around.

The Winchester 224E2 was developed for a "larger size" M1 carbine and used in the 1957 trials.
It would chamber and fire in the early AR-15 too. Stoner designed the 222 Remington Special and was tested during 1954 to 1956 and became the 5,56mm with the 223 variation in 1957.
The 222 Rem Special could not be fired in the Winchester rifle. With the 223 factory cartridge came the 222 Rem and 223 Rem Magnum variations. Interesting that Ruger introduced the Mini 14 many years later which was very popular. Both the Mini 14 and AR-15 have been chambered for the 222 Rem for export. The book "The Black Rifle" states the later on the 4.85x49mm was test in the AR-15 without any additional details. The 4,85x49 could also be considered another variation of the 222 Rem Special with the longer neck.