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Armalite’s AR-180B Patrol Carbine

Armalite’s AR-180 had its origins in the 1960s when the company set out to design a light rifle that was simple to produce, required no expensive castings, and could be made by countries with limited industrial capability using automatic screw machinery to produce rifles made largely of sheet metal stampings. The result was the AR-16 and AR-18, designed by the three-man team of Dorchester, Miller, and Sullivan.

The AR-16 was a 7.62x51mm (.308 Winchester) rifle, while the AR-18 was chambered in 5.56x45mm (.223 Remington). The AR-16 was never produced, although the AR-18 was manufactured in limited numbers. Armalite developed a commercial semiautomatic version of the AR-18 and marketed it as the AR-180.

Many firearms authorities believe that the AR-18 is a better basic design than the earlier AR-15, which developed into one of the most widely used military firearms of all time. One has only to note the number of rifle designs that are based on the AR-18 as compared to those which use the AR-15 as a starting point to see that the designers of the AR-18 clearly had something right! The AR-18 formed the basis for many military and commercial rifles, including Singapore’s SAR-80, British SA-80, Heckler & Koch’s G36, and others.

What makes the AR-18 superior? First, the gas system uses a piston and operating rod that eliminates the AR-15’s Ljungman–type gas tube that blows fouling and powder gases back into the AR-15’s receiver. Anyone who has ever fired an AR-15 or M16 knows what an onerous task cleaning is because the receiver is literally filled with carbon and powder fouling. Carbon usually winds up caked so thickly on the rear of the bolt and interior of the bolt carrier that it must be scraped or reamed away. Special tools are made to accomplish this task.

The AR-18’s piston/rod design eliminates this, dramatically reducing fouling in the receiver and bolt carrier. The AR-18’s bolt carrier rides on two rods which also carry the recoil springs. This eliminates the AR-15’s buffer tube and allows for a shorter overall length. Moreover, the bolt carrier does not directly contact the receiver, making the AR-18 much more resistant to dust and grit, a major problem with the AR-15 whose bolt carrier rides on the inside of the receiver and is subject to stoppages from dust and grime.

The latter is exacerbated by the fact that the AR-15 requires heavy lubrication to function properly.

Lubricant acts as a “dust magnet” in hostile environments, as was proven in Desert Storm, more recently in Afghanistan and Iraq, and in many other dry, dusty areas. The AR-15/M16’s susceptibility to dust mandates that the rifle’s ejection port dust cover be kept closed at all times when the rifle is not being fired to ensure reliable functioning. Although the original AR-18/180 rifles also had a dust cover, it wasn’t really necessary and the new rifles do not have this feature.

Despite the basic excellence of its design, the early AR-18/180 rifles had several flaws that prevented them from attaining their full potential. Most serious was the fact that the rifle used a special magazine. While the AR-18 magazines are identical to those of the AR-15 in shape and size, the AR-18 catch retained the magazine via a small slot on the right side, rather than the larger hole on the left of the AR-15’s magazine.

Another disadvantage was that the AR-18 magazine catch rode directly against the magazine when it was released, preventing the magazine from dropping free when the magazine release was pressed. AR-18/180 shooters had to physically pull the magazine out while pressing in on the magazine release!

There were other problems with the original AR-18s. The bolt stop was a completely different design from that of the AR-15 and rotated on a pivot. When the rifle was disassembled for cleaning, the bolt stop would almost always flop over and interfere with closing the upper receiver. It its incorrect position, the bolt stop was also subject to damage.

A lesser problem was the absence of an external bolt release, but many do not find this to be inconvenient. All one had to do to reload an AR-18/180 was insert a fresh magazine, tug the large charging handle, and release it. The AR-18/180 was also relatively crude in comparison to the AR-15, so despite its superior design, the AR-18/180 never really went far, primarily because it was completely overshadowed by its AR-15 predecessor and the fact that it was never developed to its full potential.

The most obvious change between the AR-180 and the AR180B is the lower receiver. The AR-180 lower receiver is stamped sheet steel, while the AR-180B’s is of space age carbon-reinforced polymer with steel inserts at critical points. The AR-180B lower receiver/stock assembly is virtually indestructible and is a significant improvement over the original. A second significant improvement in the AR-180B is the adoption of the AR-15 magazine release. Not only is this a better overall system, it eliminates the need to convert AR-15 magazines.

Furthermore, the AR-15/M16 magazines drop free when the release is pressed, and finally, the AR-15 magazine retention system allows use of the Ambi-Catch, a clever device which makes the magazine release fully ambidextrous. The AR-180B bolt stop still has no external bolt release, but the bolt stop has been redesigned so that it stays in place when the upper receiver is opened for cleaning. The rear sight has been modified to use AR-15 type components, again an improvement over the original which used sheet metal even for the windage knob!

The AR-180B also uses AR-15 fire controls, another improvement. The final change is barrel twist rate: the AR-180B’s twist is one turn in 9 inches rather than the original 1:12 twist rate. This allows the AR-180B to fire heavier and longer bullets of 62 grains and up, while the original rifle is limited to bullets weighing 55 grains or less.

The AR-180B carries over the original rifle’s accessory mounting plate atop the receiver, but the AR-180B’s plate is virtually useless given the lack of adapters for mounting optics. We’d prefer to have a usable MIL-STD-1913 rail mount rather than the somewhat useless “original” style mounting plate.

Although the AR-180B does not come factory equipped with a MIL-STD-1913 rail system, we were able to incorporate one by using MIL-STD-1913 handguard mounts available from Brownell’s. These are available in various lengths and while intended for mounting on AR-15 or M4 handguards, they can be mounted on an AR-180 by simply drilling a few holes and bolting them in place.

We reversed one rail and extended it back over the receiver so that we could mount an EoTech Holographic Weapon Sight and Laser Devices DBAL Dual visible and IR laser pointer. We also mounted a Laser Devices “Operative” high intensity light.

We tested the AR-180B using Black Hills and Remington match ammunition and with Winchester and Wolf 55 grain ball ammunition. We also tested Hornady 55-grain TAP Urban and Winchester 50-grain Silvertip law enforcement ammunition, as the AR-180 has excellent potential for law enforcement use.

The AR-180B performed about as expected for a rifle of its type. This is not a match rifle, nor is it intended to be. It is, however, sufficiently accurate for sporting or law enforcement use. Trigger pull of our test rifle was on the heavy side at eight pounds average, with a slight bit of creep prior to a crisp release. We shot five round groups at 100 yards off a bench using a sling.

Our groups probably would have improved somewhat if we had used a rest. The AR-180B achieved its best groups with Remington match (2.8 MOA) and Black Hills (3.3 MOA) cartridges, but all brands of ammunition delivered acceptable accuracy in the little rifle. The worst groups measured 3.9 MOA.

Functioning was flawless, with strong ejection approximately eight feet to the right front.

In sum, we found the AR-180B to be well made and 100% reliable. The AR-180B is an ideal rifle for police departments that do not wish to project a “military” image by equipping their officers with AR-15 type rifles. The AR-180B is also less expensive than most AR-15 type rifles.

We believe that the basic design of the AR-180B is superior to its AR-15 predecessor that the AR-180B will prove to be more reliable and easier to maintain than the earlier rifle. Our personal experience with the AR-180B confirms that it can be cleaned in about half the time of an AR-15 or M16. Moreover, the AR-180’s operating system is much less susceptible to foreign matter than the AR-15. As a patrol carbine, the AR-180B is highly recommended.

Charlie Cutshaw is a small arms, ammunition, and infantry weapons editor for Jane’s Defense Information. He served as an Army infantry, ammunition and intelligence officer prior to retiring in 1996. His military assignments included a tour of duty in Vietnam as an advisor. He currently lives in Alabama, where he is a full-time writer and reserve officer. He may be reached at

Published in Law and Order, Jan 2006

Rating : 7.7

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Posted on : Oct 4 at 6:26 PM By Me

repair kit for those who have a broken one

Breaking lowers..

Posted on : Oct 4 at 5:30 PM By Steve

I own a ar-180B and I haven't had any issues with the lower and BTW it is a great shooting gun! It was my understanding after speaking with a rep from Armalite that some of the very early models had issues with the lowers. I was told that they changed them by adding steel inserts and solved the problem but they never kept track of when the change was made so there is no way to tell by checking the serial numbers. I would like to see people post the production dates of the ones that have issues.


Posted on : Dec 25 at 5:43 AM By Rick Smith

This is by far one of my favorite rifle rifles to shoot, and I own AK and AR'S. I have not had any of the so called problem with the pivot pin breakage with any these rifles. I have been fairly rough with it at times. If it does break I just bought a repair kit for the future. If you want to fix it, it isn't rocket science to repair it. I wish the military would have took a little more interest in this rifle when it went to trial. I have never had a problems with jams stove piping, or any other types of problems with thousand of rounds shot through it. If they ever think about reproducing this rifles; I hope they will fix the pivot breakage problems as a lot of people claim they have had, whether they would use an aluminum ,or a stamp receiver, even though I have never had a problem with it. I so wish they would bring our a carbine, and a 300 black out caliber for it. In closing with thousands of rounds I have put through it I would not be afraid to recommend one of these for someone to buy. It often turns a lot of heads at the gun shows, and people want to learn more about it Which make me wonder why Armalite didn't promote the gun more heavily to the public with so many being curios to what I had. It not a safe queen, but none of my other black rifle are either.

Lower Pivot Connection

Posted on : Mar 12 at 12:20 AM By Doug Barron

If a person uses thier brain and opens this rifle carefully, it will not break at the hing point. I have one of these rifles and have never had any problems what so ever. I have thousands of rounds worth of experience with the M16 and can tell you for certain, this rifle is much more reliable and extreamly easy to clean in compairison. There are front hand guard products from midwest industries and also from storm werks that can transform the AR180B into a tactical accessory ready platform. Dont be afraid to buy on of these rifles, it is a great rifle at a good price. I do plan on replacing the trigger group with a drop in AR15 match trigger as the OE trigger pull is excessive. Good Shooting

AR 180B lowers

Posted on : Feb 28 at 11:38 PM By Delmar Fairchild

It didnt take long for the AR 180B to go out of production with the polymer lower breaking at the hinge as a common occurrance. If Armalite would have made a good lower, they could still make this nice rifle. Now it just lays about in two pieces for its owners.

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