Serbia’s unique Zastava M21 – Service rifles from around the world

Serbia has a long history of using the AK platform while also making small changes here and there that departed from the traditional Kalashnikov platform.

The Zastava M21 series of rifles is an excellent example of a weapon that sticks to Kalashnikov’s pattern but also makes some distinct departures.

Zastava Arms, a Serbian arms firm with a close connection to the Serbian military, built the rifle and has been producing it since 2004.

The Zastava M21 – Not NATO, but close

Although it cooperates occasionally with NATO Serbia isn’t a member of the alliance. However, its service rifle complies with NATO cartridge standards, so the M21 uses the 5.56 cartridge, rather than the traditional eastern European 7.62×39 or 5.45×39.

The M21 is Serbia’s standard assault rifle, but is also designed for export. Chambering it in 5.56 allows it to stand out in a sea of AK variants chambering eastern European calibers. Countries like Azerbaijan, Iraq, Lebanon, North Macedonia, and Peru have purchased the M21. Additionally, numerous foreign security contractors have purchased the M21 for overseas security.

Moving the AK from 5.45 to 5.56 isn’t that difficult; there aren’t necessarily any reliability issues as a whole. The rifle maintains the AK’s famed long-stroke gas-piston design with a one-piece piston and bolt-carrier group. At a glance, it looks like an AK with a much straighter magazine and black polymer furniture.

The 5.56 cartridge offers substantial benefits over the 7.62x39mm: It’s a lightweight cartridge that moves much faster, has less recoil, and is more controllable compared to the 7.62x39mm. In most ways, it’s on par with the 5.45x39mm, or at least it resides in the same ballistic vein.

Due to NATO, the 5.56 is the choice of most Western countries and has become one of the most popular rounds around the world.

The raw numbers

The Zastava M21 has an effective range of 450 meters with iron sights and 600 meters with rifle optics. While these numbers are believable, I’d argue the rifle is likely best used within 300 yards with iron sights as open iron sights make accurate shots beyond 300 yards fairly difficult.

The rifle has a three-position fire selector, offering safe, automatic, and semi-automatic modes. The rifle’s automatic mode has a fire rate of 680 rounds per minute.

There are numerous M21 variant. The basic varian uses an 18-inch barrel, which helps the 5.56 round reach higher velocities. Zastava also makes the S and C models. The S Model features a 14.8-inch barrel and the C Model a 12.8-inch one. Like most modern rifles, numerous variants exist for close-quarters combat, armored personnel carrier use, and other roles where a carbine is preferred.

The standard variant weighs 9.1 pounds, the S Model weighs nine pounds, and the C model weighs 8.6. These are heavier than most assault rifles, however, the extra weight does make the rifle easier to control.

Related: Indonesia’s Pindad SS2 – Service rifles from around the world

What’s new with the M21?

The M21 integrates a number of interesting features that make it something different than just another Kalashnikov clone.

Zastava rifles have a long history of using the heavier 1.5mm RPK receivers. The M21 also integrates the 1.5mm receiver which adds weight, but also strength. There was some discussion of reducing the profile to 0.9mms to save weight, but it doesn’t seem to have ever taken effect.

The iron sights are very simple open sights. The front post is very AK-like, but the rear sight is slightly more rearward compared to a standard AK and sits behind the ejection port and has both 300- and 500-meter settings.

The M21 features both the standard AK safety and a thumb-style safety located on the left side of the gun. This three-position safety is much easier to use, albeit somewhat awkward. When moved all the way forward, it’s in the safe position and must be manipulated rearward, towards the shooter, to engage the semi or full auto positions.

The weapon maintains the traditional AK optics mount in the form of a side-mounted rail. This means it’s limited to largely eastern European design sighting systems that position the optic fairly high on the gun. It’s still functional and usable, but far from optimum. Optics are fairly standard on Serbian service rifles and include various red dots, telescopic optics, and night vision optics.

Zastava cleverly designed the folding stock to fold to the right allowing to fold even when optics are mounted. (In contrast, many modern AK designs with folding stocks never considered that optics would need to be used at the same time as a folded stock.) The weapon’s handguard can vary. Its rail is a Picatinny option for mounting accessories. It’s common to see vertical foregrips and lights on these service rifles. The M21 can also mount a 40mm grenade launcher.

The M21 isn’t a revolutionary weapon and not the most advanced on the market. With that said, it’s still a solid weapon that follows a proven format. For countries without a massive small arms budget that are moving from Warsaw Pact to NATO guns, the M21 makes a lot of sense. It’s one of the more interesting AK variants out there.

Feature Image: Serbian gendarme holding a Serbian M21 Zastava rifle, June 2009. (Photo by Boksi/Wikimedia Commons)

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