Before the 223/5,56mm cartridge

[RCS]

Attachment 122362Attachment 122363The US Military had been testing cartridges using 224 diameter bullets during the mid 1950's.
These included the M1 carbine cartridge necked down to 224 diameter and others including the 22/7,62x51 cartridge

Around 1957, designers lengthened the 222 Remington case with a new 55 gr bullet at 3200 fps and a redesigned AR-10 rifle into a small scale called the AR-15 chambering this cartridge.
The new 1958 cartridge was called the 222 REMINGTON SPECIAL (later changed to 223 Rem)

Winchester developed a cartridge close to the 222 Rem Special and used a breech design and gas system very close to the M1 carbine. The 224E2 Winchester in 1957 fired a bullet at 3300 fps and a steel bullet at 3600 fps.

Both the Armalite AR-15 and Winchester Lightweight rifles were tested by the US Army. Final section was the AR-15 and the new 223 or later 5,56mm military

Information

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