ArmaLite AR-18: The Forgotten AR

by
posted on September 1, 2021
** When you buy products through the links on our site, we may earn a commission that supports NRA's mission to protect, preserve and defend the Second Amendment. **
AR 18

The clever engineers at ArmaLite produced a variety of cutting-edge firearms during the late 1950s and early ’60s. Many live on to this day, including the military M-16, its M4 sibling currently fielded by our troops and the commercial AR-15. All cycle by direct gas impingement, but Eugene Stoner—who is credited for the original design—knew the method of operation wasn’t necessarily the final word in reliability and performance.

Likely he didn’t think the AR-16 he created during the same period was either, although the short-stroke piston driven design is largely recognized today as running cleaner. The rifle was chambered in 7.62 NATO and the company hoped the U.S. Military would adopt it as a less-expensive replacement for its aging fleet of M1s.

The sales pitch didn’t work, then ArmaLite sold the rights to the AR-15 to Colt’s Manufacturing, and Stoner left the company. Meanwhile, Arthur Miller and his team, still at the firm, improved on the AR-16 design, gave it a new 5.56 NATO chambering, and the AR-18 was born. A commercially available version, the AR-180, later hit the U.S. market.

Both guns are a far cry from the AR-15, though. The piston-driven method of operation uses a rotating bolt, but a pair of rods with springs guide the bolt carrier group during cycling. The reciprocating charging handle was located on the right side, attached to the bolt carrier group and the metal stock could be folded to the side.

Magazines were not compatible with AR-15 versions and the gun was built from stamped and welded steel. It’s a manufacturing approach not exactly known for tight tolerances, although that fact often ensures operation through miserable conditions.
In 2001, the new owners of ArmaLite reintroduced the rifle as the AR-180B. Its improvements included the ability to use AR-15 magazines, straight charging handle, polymer stock and more. Dave Campbell took a longer look at the history and the new gun—which was discontinued in 2007—for American Rifleman a couple years back.

When he wrote the story, in 2018, used specimens of the rifle were selling for between $900 and $2,500. Most guns for sale today command prices anywhere from $2,500 to $3,000, with many above that range.

Latest

FP 6.5Peak Launch Fusion Terminalascent Peakalloy 19
FP 6.5Peak Launch Fusion Terminalascent Peakalloy 19

Federal's New 6.5 Creedmoor +Peak: The Peak Alloy Case Goes Mainstream

Federal introduced its high-pressure Peak Alloy case design with the 7 mm Backcountry in 2025. Now, the company is incorporating it into high-pressure 6.5 Creedmoor loads with the +Peak design.

I Carry: Springfield Armory Echelon 4.0FC in a JM Custom Kydex Holster

In our latest "I Carry" video, a Springfield Echelon 4.0FC is outfitted with Aimpoint's new COA enclosed-emitter red-dot optic, and to carry this optic-equipped handgun, we've selected a JM Custom Kydex holster.

The Armed Citizen® June 5, 2026

Read today's "The Armed Citizen" entry for real stories of law-abiding citizens, past and present, who used their firearms to save lives.

Multi-Caliber MK24 to Replace SCAR-H For SOCOM

U.S. Special Forces will soon be replacing their 7.62-NATO-chambered SCAR-Hs with a new, barrel-swapping MK24 Mid-Range Gas Gun-Assault (MRGGA) gun capable of running either 7.62 NATO or 6.5 Creedmoor.

Rifle Renaissance 2026: Exploring Rifle Skills Beyond Marksmanship

Being able to shoot in contextual situations, shoot from unusual positions, manipulate the rifle quickly and rapidly adjust one’s position based on distance are all essential skills for a well-trained rifleman. To train these abilities, The Complete Combatant hosted the first annual Rifle Renaissance event in March 2026.

New Guns For 2026: A Full Guide

While it’s claimed the firearms industry is experiencing a slowdown, that hasn’t meant a stall to innovation. It means gunmakers are working harder than ever to earn your business.

Interests



Get the best of American Rifleman delivered to your inbox.