The company was constantly growing, employing 490 people in 1917,[1] 990 in 1920 and over 5000 in 1923, although the Great Crisis forced it to downsize and slow production.

After the war, the communist government of the People's Republic of Poland, renamed (in 1953) the company to the "Joseph Stalin Metal Works in Poznań" (Zakłady Metalowe im.

In the early 1990s, as part of their preparations to join NATO, the Polish armed forces began looking for a replacement for the PK-series machineguns they had in service.

Cegielski proposed a prototype (code-named PKM-NATO) that modified the PK/PKS to feed standard 7.62×51mm NATO cartridges and use NATO-standard ammo belts.

The modifications included a heavier barrel, a larger chamber, and a redesign of the lock, extractor, and the entire feeding mechanism.