Armalite was flying high off their AR-15 design and had recently sold the rights to Colt to produce the weapon for the United States military. Success doesn’t stop with one hit, so the folks at Armalite set out to design the next big thing. Since Colt owned the AR-15 design, they couldn’t rely on elements of that firearm. They had to start essentially from scratch. Enter the AR-18.

With the AR-18, they wanted to offer an alternative and even a competitor to the AR-15 for countries that couldn’t afford to purchase AR-15 firearms. The 5.56 round was catching on, and countries were looking to replace their old 7.62 NATO battle rifles. In fact, Armalites goal was to both sell rifles and licenses. Armalite designed the rifle to be simple to produce. To that purpose, it used stamped metal, much like the famed AKM series of rifles.

The AR-18: Armalite's Innovative Failure of a Rifle
Testing of the AR-18. (DoD)

This simplified construction would make the rifle easier to produce for less technically savvy companies. So, Armalite could sell a batch of AR-18s to a military and then grant them the license to build their own rifles domestically. This would allow Armalite to make a passive income off the design and allow countries to domestically manufacture their own firearms and reduce their dependence on foreign production.

Armalite also produced the AR-180, which is the semi-auto, civilian version of the AR-18 for commercial sale. The AR-180 was identical to the AR-18 outside of the selective fire capability. Additionally, a model known as the AR-18S was made that featured a short carbine length barrel and selective fire capability.

What Makes Up the AR-18

The AR-18 and AR-180 series of rifles use a completely different system than the AR-15. Armalite consciously wanted to avoid infringing on the AR-15. As such, a direct impingement system was abandoned for a short-stroke gas piston system. Short-stroke gas piston systems function extremely well for short-barreled guns, but sadly there wasn’t much of a call for short carbines in the 1960s.

The original AR-18 and AR-180 series of rifles didn’t utilize the traditional AR-15 magazine either. They used their own 20-round aluminum magazine that was similar but separate from the AR-15’s. You could even modify M16 magazines to fit the AR-18.

The AR-18: Armalite's Innovative Failure of a Rifle
(Courtesy Vickers Tactical)

The AR-15 uses smooth and refined forged uppers and lowers. On the other hand, the AR-18 took some Soviet inspiration and used stamped steel and welds. As such, the AR-18 was not a pretty gun by any means. It was rough but functional. Yet, the AR-18 proved to be both reliable and accurate. From a design perspective, it was not a bad gun.

The ergonomics included a more traditional right-handed charging handle with what Armalite called a “Dog Leg.” Armalite included a massive magazine release that was very easy to reach and activate. The safety was ambidextrous and certainly ahead of its time.

The short-stroke gas piston system eliminated the need for a buffer and buffer tube, so Armalite was free to produce a side folding stock for transport and size reduction. The gun rocks an 18.5-inch barrel on the AR-18 and AR-180 design. This takes decent advantage of 5.56 ballistics and makes the gun a smooth shooter.

An Influential Failure

The AR-18 never saw any real success in the market. It turned out to be cheaper to buy M16s from the U.S. government or to rely on the widespread Soviet AK than to build the facilities to make your own AR-18s.

Nevertheless, Armalite sold the license here and there. A Japanese company called Howa purchased the rights to the rifle and produced the Howa Type 89 assault rifle for the Japanese Self-Defense Force. In the U.K., the Sterling Armaments Company purchased the rights and produced a number of AR-18 and AR-180 series rifles.

The AR-18: Armalite's Innovative Failure of a Rifle
Wikimedia Commons

Unfortunately, for Armalite, the Irish Republican Army adopted the AR-18 and AR-180 series rifles. They became a symbol for the IRA’s cause and served as the most modern rifle of its forces.

These rifles came to Ireland from famed smuggler George Harrison. Reportedly, they were a mix of American purchased AR-180s and AR-18s that came from a Corsican arms dealer. However, this claim doesn’t seem to be verifiable.

The AR-18 became such a popular rifle in Ireland that songs were written about it. My Little Armalite made quite the impression in Ireland.

While the rifle was never extremely popular, it became incredibly influential in modern small-arms design. Rifles like the FS2000, the SCAR, the G36, the L85, and Singaporean SR-88 all have design influences from the AR-18.

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The Modern Comeback

You can’t keep a good rifle down, and as of late, the AR-18, or more appropriately, the AR-180, has made a comeback. Brownells has taken the design and modified it extensively to function with standard AR-15 lower receivers. It still uses the core AR-180 systems but has been modernized with an M-LOK and an optics rail. It now fits perfectly on a mil-spec AR-15 lower. You can find a hundred different AR 15s for sale, but how many AR 18s will you find?

The AR-18: Armalite's Innovative Failure of a Rifle
(Gunmag Warehouse)

I own one and love it. It’s a solid and smooth shooting rifle that mounts a folding stock. Obviously, it works with standard AR-15 magazines and provides a modernized alternative to the AR-15.

The AR-18 wasn’t a success in its day, but not to any mechanical fault of its own. It was always a well-made rifle that was accurate and reliable. It simply wasn’t meant to be.

It’s an influential failure that’s made quite the comeback. This proves you can’t keep a good rifle down.

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