It was not until 1990 that production approval was given for the first prototypes, evaluated the following year in a series of military qualification tests resulting in an order for an initial pre-production batch in 1993, to be manufactured at the Łucznik Arms Factory in Radom.

The Onyks was designed to equip airborne infantry, police and military special operations units and vehicle crews.

The carbine has an identical design layout, system of operation, locking mechanism and uses the same type of ammunition as the Tantal rifle, and the main modifications include the following components: the barrel, bolt carrier and piston rod, gas cylinder, foregrip, heatguard, muzzle device and iron sights.

Compared to the Tantal, the Onyks features a barrel reduced in length by 216 mm (8.5 in), fitted with a different type of muzzle device.

Due to the barrel's length, this device is primarily used to reduce muzzle flash, but it can also be used to mount and launch rifle grenades.

At its muzzle end, the device has a conical flash hider, and on its tapered, external surface – a retainer spring and two collars, used to attach and guide rifle grenades.