sa81 KRASA: Czechoslovakia's Ultra-Compact Lost PDW
22m
The Krása project (which translates as "beauty", but is also a shortening of "short assault rifle" - "KRÁtký SAmopal") is a fascinating piece of Czech small arms development. In 1976, the Czechoslovakian military requested development of a compact personal weapon for special troops (paratroops, armored vehicle crews, etc) and unit commanders. It was to be chambered for the standard 7.62x39mm cartridge, but it should be no more than 1.6kg (3.5lb) empty and just 270mm (10.6") long when folded.
The project was tackled by Jiri Čermák, who was the designed of the vz58 rifle. He began by simply shortening a vz58 as much as possible, but that was not sufficient to meet the goals. So he went on create a new rifle with a radically different feeding system. Instead of pushing rounds forward out of the magazine, it would pull them rearward, like a Mars or Boberg pistol (or like the North Korean Type 73 machine gun). This required a very different type of magazine, but allowed Čermák to create a functional weapon that was close to the requested size - 315mm (12.4") long and 2.1kg (4.6lb).
The first prototype was designed in late 1980, and two examples were made in 1981, designated the sa81. After only a small amount of function testing, the project shifted to use the new 5.45x39mm cartridge. One example in that caliber was made, the sa83, in 1983. However, the project was cancelled at the end of 1983 in favor of the new Lada program, which planned to create a complete new family of small arms. Lada was in turn cancelled by the fall of communism, and eventually replaced by the short-lived CZ2000 family in 5.56x45mm.
The Krása project made a brief comeback around the same time as the CZ2000, called project HROM. It uses the exact same mechanism, but with distinctive elements from the Lada/2000 guns like the sights and furniture. That project also was cancelled after just a couple prototypes.
In my opinion, the reverse-feeding concept remains a fascinating potential solution for an ultra-compact PDW. Seeing someone finish its development using a cartridge like .300 Blackout today would be awesome...
Thanks to the Czech Military History Institute (VHU) for graciously giving me access to this one-of-a-kind prototype to film for you! If you have the opportunity, don't miss seeing their museums in Prague:
https://www.vhu.cz/en/english-summary/