Zastava M21
- Category
- Assault Rifle
- Barrel
- 460 mm
- Weight, empty
- 3.60 kg
- Introduced
- 2004
About
What it is, and why it matters
The Zastava M21 is a select-fire assault rifle chambered in 5.56x45mm NATO, produced by Zastava Arms since 2004. This Serbian-manufactured firearm reflects the engineering traditions and quality standards of its country of origin, designed to meet the demands of both civilian and professional users in a competitive global marketplace. Featuring a 30-round magazine capacity, this assault rifle offers generous firepower for duty use and home defense. The 18.1-inch barrel maximizes accuracy potential and ballistic performance, making this an excellent choice for target shooting, competition, or field use. At 3600g (127.0 oz), this is a substantial firearm whose weight contributes to reduced felt recoil and enhanced stability during precision shooting. The steel frame provides a solid, premium feel with the durability to withstand decades of regular use and thousands of rounds. This firearm represents its manufacturer's commitment to delivering a well-engineered, reliable product that serves the needs of discerning shooters seeking quality, accuracy, and dependable performance from a proven platform.
The M21 represents Serbia's attempt to modernize its infantry weapon into NATO compatibility while preserving decades of institutional knowledge with the AK platform. Despite its adoption, Serbia has not fully transitioned from the 7.62x39mm M70, and both calibers remain in parallel service -- a pragmatic acknowledgment that NATO membership, while pursued, has not yet been achieved.
The M21 represents Serbia's transition from Soviet-era 7.62x39mm to NATO-standard 5.56mm while preserving the proven Zastava AK platform. The bulged 1.5mm trunnion inherited from the M70 provides superior receiver rigidity. The M21S is a compact carbine variant with shortened barrel. The M21 ABS (Advanced Buttstock System) variant adds improved ergonomics. Despite adoption, Serbia has not fully transitioned from the M70, with both calibers remaining in parallel service. The rifle competes in the same market as the Polish Beryl and Russian AK-101 as NATO-caliber AK derivatives.
Specification
Everything measured
IdentityWhat it is, who built it and when.
- Manufacturer
- Zastava Arms
- Category
- Assault Rifle
- Country
- Serbia
- Status
- In production
- Produced
- 2004
- Variant of
- Modernized
DimensionsAs issued, without a magazine or an optic.
- Barrel
- 460 mm
- Overall length
- 1000 mm
- Weight, empty
- 3.60 kg
- Weight, loaded
- 3.95 kg
ActionHow it cycles, what trips it, and what feeds it.
- Action
- Gas operated long stroke
- Firing mechanism
- Hammer fired
- Trigger
- Single stage
- Capacity
- 30
- Magazine
- Detachable box
MaterialsEach swatch is the material itself, not a colour chosen to stand for it.
- Frame
- Steel
- Barrel
- Steel
- Stock
- Polymer
- Finish
- Matte black
BallisticsFrom the service cartridge, not a handload.
- Muzzle velocity
- 920 m/s
- Muzzle energy
- 1700 J
- Effective range
- 600 m
- Maximum range
- 1000 m
- Rate of fire
- 680 rpm
Trajectory
What the round does downrange
Solved from the muzzle figures and the bullet. The dashed rule is the effective range on the record, and the crosses are the steps the solver returned.
Features
What it has
What the record lists as fitted, drawn from the catalogue.
Chrome lined barrel
Cold hammer forged barrel
Rotating bolt
Select fire
Side folding stock- Bulged trunnion 1 5mm
Picatinny rail top
Three cooling vents handguard
Nato standard ammunition
Standing
How it compares
Each figure against the firearms of the same type and cartridge that record it, or of the same type where that cartridge has too few. Positions are read to the nearest tenth.
| Measurement | This firearm | Median | Position |
|---|---|---|---|
| Empty weightAmong 158 5.56x45mm NATO assault rifles | 3.60 kg | 3.60 kg | Near the median |
| Overall lengthAmong 156 5.56x45mm NATO assault rifles | 1000 mm | 920 mm | Longer than about 90% |
| Barrel lengthAmong 157 5.56x45mm NATO assault rifles | 460 mm | 449 mm | Longer than about 70% |
| Magazine capacityAmong 158 5.56x45mm NATO assault rifles | 30 | 30 | Near the median |
Answers
Questions about the Zastava M21
How much does the Zastava M21 weigh?
The Zastava M21 weighs 3.60 kg (7.94 lb) empty and 3.95 kg (8.71 lb) loaded.
What caliber is the Zastava M21?
The Zastava M21 is chambered in 5.56x45mm NATO.
How many rounds does the Zastava M21 hold?
The Zastava M21 holds 30 rounds, fed from a detachable box magazine.
How long is the Zastava M21?
The Zastava M21 is 1000 mm (39.4 in) long overall, with a 460 mm (18.1 in) barrel.
Who makes the Zastava M21?
The Zastava M21 is made by Zastava Arms (Serbia).
When was the Zastava M21 introduced?
The Zastava M21 was introduced in 2004.
How does the Zastava M21 operate?
The Zastava M21 uses a gas operated long stroke action, and its firing mechanism is hammer fired.
Compatibility
Which parts fit this firearm
Studio
Every part that mounts on this, resolved
Not a list the maker typed out: the answer comes from the mounts this firearm exposes and the interface each part needs, so it stays right when either one changes.
- Every part that mounts on any firearm in the catalogue
- Interface standards, platforms and fit overrides
- The same answers through the API and the MCP server
Requires a signed-in GunSpec account on the Studio plan. The answer is computed per part, so it is not part of the public record.
Provenance
What the record holds
Every figure above was taken from one of these pages. The confidence reflects how much of the record came from a page a claim can be checked against.
In service
- Serbian Armed Forces
- 2004
- Serbian Police
- Serbia
Provenance
Confidence in this record
83%
Stockists
Where to buy
Offers link straight to the shop. GunSpec never takes the order.
No shop has listed this firearm yet
Stock and prices come from the shops themselves. If you sell this firearm, you can list it and it appears here.
List a firearmMCP
Ask an assistant about it
The same record, reached the way a person asks for it rather than the way a program does.
Ask GunSpec
Works with
Point an MCP client at GunSpec and it answers from the catalogue rather than from memory. A free key covers the read tools.
API
The call that returns this record
The same fields, in the same units, from the same endpoint the page reads.
curl --request GET \ --url 'https://api.gunspec.io/v1/firearms/zastava-m21' \ --header 'X-API-Key: your_key'{ "id": "zastava-m21", "name": "Zastava M21", "manufacturer": { "id": "zastava", "name": "Zastava Arms", "countryCode": "RS", "foundedYear": 1853, "website": "https://www.zastava-arms.rs", "logoUrl": null, "description": null, "status": null, "defunctYear": null, "stateOwned": null, "makesFirearms": null, "parentId": null, "predecessorId": null, "createdAt": "2026-02-18 03:40:48", "updatedAt": "2026-02-18 03:40:48", "version": "1280b11f95e216b0481865c8371fa30b9f7a5b33a8167e7b5ba6166da29d4149" }, "category": { "id": "assault-rifle", "name": "Assault Rifle", "description": "Selective-fire rifles chambered in intermediate cartridges" }, "country_of_origin": "RS", "year_introduced": 2004, "barrel_length_mm": 460, "weight_empty_g": 3600, "action_type": "gas_operated_long_stroke"}