Soviet 5,6x39mm

Back in the 1950's the Russians necked down their standard 7,62x39mm to use a .223 diameter bullet. this became the 5,6x39mm cartridge with a velocity of around 3,000 fps.
It was tested in some Soviet assault rifle designs and end result was the 5,45x39mm cartridge as used in the AK-74.

Another application of this 5,6mm cartridge was in the hunting world as Finland manufactured this cartridge where it was known as the 220 Russian. SAKO manufactured a small ring Mauser rifle for the cartridge (I have also seen a 7,62x39mm SAKO small ring Mauser rifle years ago at the Gun Digest )

US benchrest shooters also developed the 22 PPC and 6mm PPC from the 220 Russian

photo shows: 5,45x39mm, 220 Russian and 7,62x39mmAttachment 88891

I remember when this cartridge first surfaced and the guns were coming back from Afghanistan through the black market...our int guys had a few and were trialling them in Camp Borden ON. I came across a stack of cases on the firing point when the live cartridges were worth $100 each to collectors...that was during gulf war one...('90/'91?)