The PK-102 is an assault rifle found in the Syphon Filter games. Its real-world counterpart is the AK-74, a descendant of the legendary AK-47 (though there is a PK series as well, but the real-world PK series is a machine gun, and not an assault rifle).
"A variant of the the popular Vokinhsilak* system (one of the most widely used and modified designs in the world), the PK-102 is a compact, lightweight, full assault rifle that is easy to conceal, making it a popular choice for terrorists."
In the SF1, the PK-102 is described as a variant of the 'Vokinhsilak system'. This was changed in SF2 and carried over in 3 as a variant of the Kalashnikov. "Vokinhsilak" is Kalishnikov (a typo for "Kalashnikov") spelled backwards.
In SF3, the PK-102 has a different appearance, although the instruction manual still uses the old version.
PK-102 (or AK-74) are oftenly used by enemies in the countries that related to the former Soviet Union e.g. Kazakhstan, Russia and Afghanistan during Soviet occupation in cold war era.