Back to the AK-74…Most of the Commie countries outright copied the Soviet pattern AK-74, but they also added some of their own twists. For example, the FSB on the Romanian AK-74 rifles is unique because the bayonet lug is directly below the sight, where as everyone else placed theirs on an extension behind the FSB. This also required the Romanians to use a unique 22mm muzzle brake that was not interchangeable with the 24mm size used by the other countries.
Common lug and brake.
Romanian lug and brake.
The Romanians also decided to keep the 45 degree gas block from the original AK074 instead of changing to the new 90 degree style used in the modern AK-74 produced after 1977. Here is the original AK-74, circa 1974 (duh).
When the Warsaw Pact countries looked at switching over to the 5.45 caliber, some, like the Poles, asked about obtaining license rights from the Russians to manufacture their own AK-74s. The Russians however, made such a venture very expensive, so much so that the Poles decided to alter the basic design enough that they would essentially have a different rifle that still fired the common round.
Polish Tantals also use proprietary components on their version of the AK-74 and are probably the greatest departure from the standard AK-74 design from any country. The Tantal uses a different muzzle brake than standard AK-74s that permits the firing of rifle grenades, modified mainsprings, handguards, handguard retainer, gas tube, gas tube retainer, FSB, and a few other details. Tantals use a very unique combination of the standard AK safety selector on the right side of the receiver and a fire control selector on the left side based on the FNC design. The right side setting "Z" (Zabezpieczony) worked like the standard AK safety, while the "0" (Odbezpieczony) setting activates the 3-position selector on the left side. "C" (Ciagly) is for full auto, "P" (Pojedynezy ) is for semi-auto, and "S" (Seria) for a three-round burst on the fire control selector. On real Tantals, the ratchet mechanism resets itself after the trigger is released so pulling the trigger again gives you three rounds, not the remainder of what was left before you released the trigger.
The AKM receiver also served as the basis for AKs in other calibers, especially the 5.56x45 NATO. The Russians, Romanians, Hungarians, Bulgarians, East Germans, Yugoslavians, and Chinese have all built 5.56mm chambered AKMs. The Bulgarians have also taken their manufacturing prowess one step further and built milled AKs in 5.56 and 5.45mm.