ArmaLite AR-180

ArmaLite · Rifle · Out Of Production · 1969

Also known as: AR-180, Widowmaker, Sterling AR-180

Overview

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).

Specifications

Weight (empty)	3170 g (111.8 oz)
Weight (loaded)	3500 g (123.5 oz)
Overall Length	940 mm (37.01")
Folded Length	738 mm (29.06")
Barrel Length	464 mm (18.27")
Action Type	Gas Operated Short Stroke
Firing Mechanism	Hammer Fired
Trigger Type	Single Stage
Magazine Capacity	20 rounds
Magazine Type	Detachable Box
Muzzle Velocity	990 m/s (3248 fps)
Muzzle Energy	1796 J (1325 ft·lbf)
Effective Range	460 m (503 yd)
Maximum Range	2700 m (2953 yd)
Barrel Rifling	Right Hand
Rifling Twist	305 mm (12.01")
Number of Grooves	6
Frame Material	Stamped Steel
Barrel Material	Steel
Stock Material	Polymer
Finish	Phosphate

Calibers

5.56x45mm NATO · primary · 5.56x45mm NATO — also known as .223 Remington, 5.56 NATO

Features

Firing modes: Semi Automatic
Feed systems: Detachable Box Magazine
Safety mechanisms: Manual Safety, Trigger Block Safety
Features: Side Folding Stock, Stamped Sheet Metal Receiver, Short Stroke Gas Piston, Rotating Bolt, Three Pronged Flash Suppressor, Carry Handle, No Buffer Tube

Variants

ArmaLite AR-18 (select-fire military) — Fire Control
ArmaLite AR-180B (2001 reintroduction with polymer lower) — Frame
Sterling AR-180 (UK production 1979-1985) — Manufacturer
Howa AR-180 (Japanese production 1970-1974) — Manufacturer

Service history

Operators

Provisional IRA · adopted 1971 · as Widowmaker
Civilian market (US, UK, Japan) · adopted 1969 · as AR-180 Sporter

Conflicts

The Troubles (1968-1998)

Production

Estimated total produced: 20,352 · Production years: 1969-1985

ArmaLite (Costa Mesa) ~4,018; Howa (Japan) ~3,972; Sterling (UK) ~12,362. AR-180B reintroduction (2001-2007) produced an unknown additional quantity

Origin

Country of origin: United States

Designer: Eugene Stoner / Arthur Miller

Discontinued: 1985

Notes

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.

Background

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.