ArmaLite AR-180
- Category
- Rifle
- Barrel
- 464 mm
- Weight, empty
- 3.17 kg
- Introduced
- 1969
About
What it is, and why it matters
The ArmaLite AR-180 is the semi-automatic civilian export version of the select-fire AR-18, designed by Eugene Stoner, Arthur Miller, George Sullivan and Charles Dorchester at ArmaLite in 1963 as a simplified, manufacturing-friendly successor to the AR-15/M16. Introduced commercially in 1969 and chambered in 5.56x45mm (.223 Remington), the AR-180 substitutes a stamped sheet-metal receiver for the AR-15's machined aluminum forging and replaces the AR-15's direct-impingement gas system with a short-stroke gas piston that exhausts gas before it reaches the bolt carrier - an arrangement that produces a much cleaner, cooler-running action. Its receiver-mounted bolt carrier and side-folding polymer stock eliminate the AR-15's receiver-extension buffer tube, allowing the rifle to be fired with the stock folded. Production was split across three factories: ArmaLite in Costa Mesa (1969-1972, ~4,018 rifles), Howa Machinery in Japan (1970-1974, ~3,972 rifles), and Sterling Armaments in Dagenham, England (1979-1985, ~12,362 rifles).
Engineers consider the AR-180 the rifle that should have replaced the M16 - it was simpler, cleaner, and cheaper to manufacture - but it was rejected by every major military it was offered to. Instead its design DNA seeded a generation of successors, from Britain's SA80 to the Bushmaster ACR. In Northern Ireland the IRA gave it a darker legacy: smuggled by the boatload from the United States, the AR-180 became 'the Widowmaker' for its devastating effect on RUC checkpoints during the Troubles.
Although the AR-180 never achieved meaningful military adoption, its short-stroke gas piston and stamped-sheet-metal lower influenced an enormous range of later designs including the SA80, SAR-80, Singapore SR-88, Howa Type 89, and the Bushmaster ACR. The Provisional IRA acquired several hundred AR-180s smuggled from the United States during the 1970s; the rifle's destructive power against soft-skin vehicles and police checkpoints earned it the nickname 'Widowmaker' in Northern Ireland. ArmaLite re-released a polymer-lowered AR-180B from 2001 to roughly 2007.
Specification
Everything measured
IdentityWhat it is, who built it and when.
- Manufacturer
- ArmaLite
- Category
- Rifle
- Country
- United States
- Status
- Out of production
- Produced
- 1969 to 1985
DimensionsAs issued, without a magazine or an optic.
- Barrel
- 464 mm
- Overall length
- 940 mm
- Weight, empty
- 3.17 kg
- Weight, loaded
- 3.50 kg
ActionHow it cycles, what trips it, and what feeds it.
- Action
- Gas operated short stroke
- Firing mechanism
- Hammer fired
- Trigger
- Single stage
- Capacity
- 20
- Magazine
- Detachable box
MaterialsEach swatch is the material itself, not a colour chosen to stand for it.
- Frame
- Stamped steel
- Barrel
- Steel
- Stock
- Polymer
- Finish
- Phosphate
BallisticsFrom the service cartridge, not a handload.
- Muzzle velocity
- 990 m/s
- Muzzle energy
- 1796 J
- Effective range
- 460 m
- Maximum range
- 2700 m
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.
Side folding stock
Stamped sheet metal receiver
Short stroke gas piston
Rotating bolt
Three pronged flash suppressor
Carry handle
No buffer tube
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 84 5.56x45mm NATO rifles | 3.17 kg | 3.08 kg | Heavier than about 60% |
| Overall lengthAmong 77 5.56x45mm NATO rifles | 940 mm | 900 mm | Longer than about 80% |
| Barrel lengthAmong 98 5.56x45mm NATO rifles | 464 mm | 406 mm | Longer than about 90% |
| Magazine capacityAmong 98 5.56x45mm NATO rifles | 20 | 30 | Holds fewer rounds than about 90% |
Answers
Questions about the ArmaLite AR-180
How much does the ArmaLite AR-180 weigh?
The ArmaLite AR-180 weighs 3.17 kg (6.99 lb) empty and 3.50 kg (7.72 lb) loaded.
What caliber is the ArmaLite AR-180?
The ArmaLite AR-180 is chambered in 5.56x45mm NATO.
How many rounds does the ArmaLite AR-180 hold?
The ArmaLite AR-180 holds 20 rounds, fed from a detachable box magazine.
How long is the ArmaLite AR-180?
The ArmaLite AR-180 is 940 mm (37.0 in) long overall, with a 464 mm (18.3 in) barrel.
Who makes the ArmaLite AR-180?
The ArmaLite AR-180 is made by ArmaLite (United States). It was designed by Eugene Stoner / Arthur Miller.
When was the ArmaLite AR-180 introduced?
The ArmaLite AR-180 was introduced in 1969 and discontinued in 1985.
How does the ArmaLite AR-180 operate?
The ArmaLite AR-180 uses a gas operated short 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
- Provisional IRA
- 1971
- Civilian market (US, UK, Japan)
- 1969
Provenance
Confidence in this record
82%
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/ar-180' \ --header 'X-API-Key: your_key'{ "id": "ar-180", "name": "ArmaLite AR-180", "manufacturer": { "id": "armalite", "name": "ArmaLite", "countryCode": "US", "foundedYear": 1954, "website": "https://armalite.com", "logoUrl": null, "description": "US-based firearms manufacturer in Bryan, Texas. Originally founded in 1954 by George Sullivan as the light firearms division of Fairchild Engine and Airplane Corporation. Best known for developing the AR-15 platform under chief designer Eugene Stoner. Revived in 1996 and currently owned by Strategic Armory Corps.", "status": "active", "defunctYear": null, "stateOwned": null, "makesFirearms": true, "parentId": null, "predecessorId": null, "createdAt": "2026-02-18 03:40:42", "updatedAt": "2026-02-18 03:43:38", "version": "503417c9bae93d8a5e31f82fd1ac3105101d450da1a5245551cc6ddffa528358" }, "category": { "id": "rifle", "name": "Rifle", "description": "Long-barreled firearms designed for accurate shooting" }, "country_of_origin": "US", "year_introduced": 1969, "barrel_length_mm": 464, "weight_empty_g": 3170, "action_type": "gas_operated_short_stroke"}