Zastava M21

The Zastava M21 is a Serbian assault rifle developed by Zastava Arms as an evolution of the Yugoslav/Serbian Kalashnikov-derived rifle family. Unlike the older 7.62x39 mm M70, it is chambered for 5.56x45 mm NATO, reflecting Serbia's interest in export compatibility and modernization. The rifle entered Serbian service in the 2000s and has been offered in several barrel-length variants.

M21 retains the long-stroke gas-piston Kalashnikov architecture while using 5.56 mm ammunition, modern furniture, folding stocks, muzzle devices, and optics rails on many versions. It is available in full-length, carbine, and short-barrel configurations. Its design balances familiar rugged mechanics with a cartridge and accessory ecosystem better aligned with NATO and export markets.

Operationally, the M21 serves as a modern infantry rifle for Serbian forces and export users that want AK reliability in a 5.56 mm package. It is not a radical new rifle design, but a practical modernization of an established national weapons lineage. Its importance lies in Serbia's ability to keep domestic rifle production relevant after Yugoslavia's breakup and amid changing ammunition standards.