I may have posted about this round before, but I recently dug-up an article I had stashed and took some pics. The following is taken from that article on “Urban-Use Cartridges” from a number of countries:
-The .223 IMI round is designed for use in modified Mini-Uzi and Micro-Uzi machine-pistols.
-The 5.56 bullet weighs 3 grams.
-The case is a reduced and shortened 5.56x45 case.
-Muzzle velocity is 580 m/sec.
-Effective against most protective vests, but designed to remain inside the body and not be dangerous to others in the area.
I should add that I don’t think this project really went to full-scale production. I saw some airport barrier security, back in 1992 or so, that had Mini and Micro-Uzis with white stripes on the grips and mags. I remember thinking at the time that they might be using the .223 IMI round, but never confirmed.
Bullet diameter: 5.47mm
Case length: 22.95mm
Overall length: 30.15mm
Variations known: ball, dummy with case hole and blue base.