Do you mean AK 47 or 74 variant? The AKS-74U was the original Soviet short-barrelled machinegun. Several other countries also made a variant, the Polish Onyx (5.45) and Mini-Beryl (5.56), Galil MAR carbine (5.56), Hungarian AMD-65 (7.62mm), AK 104 (7.62), AKMS-U (7.62)
What sort of markings are on it? What of the flash hider? etc.