Saturday, September 13, 2008

The Armalite AR180b, piston powered from the start

The whole world knows the shape and sound of the US military's M-16 rifle. In service since the 1960's in one form or another, the weapon platform has seen use in battles across the entire globe. Not quite as well known is it's history, or the man mostly responsible for the M-16 with it's gas impingement form of action.

Eugene Stoner was working for Armalite when he conceived the AR design of rifle. Through various trials it found it's way into the military inventory and first saw service in Southeast Asia. Amidst complaints of reliability issues, Stoner redesigned the rifle (the AR-18) and reverted back to the short stroke gas piston. The military decided to stay with it's M-16 investment, and corrected it's ammunition and training issues that were the root cause of the M-16's issues.

Over the years, Stoner's updated and improved AR-18 design found favor with arms makers outside the US, and Morphed into many well known military weapons of the century, although it never came home to the US military. H+K especially liked the design, and borrowed many parts of it for their battle rifles. The Stoner AR-18 shadow falls heavily on the SA80, the SAR80, and the G-36.

On the home front, both the Armalite company and the AR-18 patent saw new owners and countries. The AR-18/ AR-180 itself became as much a collectors rifle as a shooter. Sometime around the year 2000 a reformed Armalite redesigned the AR-180 again, into the AR180b, and began production.

The AR180b combined the best features of the AR-15 and the AR-180 into one lightweight and dependable package. Never designed for full automatic fire, it's sales were aimed at the civilian and police markets. Introduced at a price several hundred dollars less than the competition's AR-15 rifles, it should have taken off well, and would have if dealers had not universally raised the price to AR-15 levels as it hit the store racks. After all, it was black and looked like an AR-15, so why shouldn't they get full AR retail for it?

Armalite still makes the AR180b, and it has a small but loyal following. Knowledgeable AR180b owners are now having giggling fits as they read articles loudly announcing new short stroke piston kits for the AR-15/M-16 rifles, the AR180b having had this reliable action from the beginning.


The AR180b weighs in at just over six pounds, and that's with a full length barrel. Much of the weight savings came from making the lower receiver of high strength plastic. For any normal service the receiver is indestructible, and will survive things that would destroy an AR-15. While redesigning the lower unit, Armalite built it to use standard AR-15 magazines and an AR-15 trigger group. This allowed the use of all the surplus magazines on the market, and also made repairing any trigger issues a breeze, with parts available from a dozen sources.

The upper unit is where things get different. A shooter need only use a cartridge to depress a plunger at the back of the action, and it will tilt apart similar to an AR-15. The similarity is only cosmetic, as everything else is different. Very different.

The bolt does not ride against the receiver, excepting a stud used to rotate the bolt head. This makes the action very reliable in dirty conditions, having room for debris to fall free. Instead, the bolt rides on two long rods, which also guide the recoil springs. Both rods and springs are contained in the receiver, unlike the AR-15. This means the AR180b (and AR-180) can have a real folding stock.

The bolt is acted on by a short stroke gas piston riding above the barrel under the upper forearm. Having removed the bolt and guide rods, the forearm can simply be lifted off and the entire gas system cleaned and serviced. The entire field stripping can be done with no tools, and achieved in under a minute. Reassembly is slightly more fiddly, with care needed to properly insert the bolt into the receiver, but can still be done in a about a minute.

Unlike the AR-15 type rifle, with the AR180b no gas enters the action. This increases reliability and makes cleaning a breeze. No more digging hardened carbon out of the bolt head!

Another major difference incorporated into the AR180b, the charging handle is a knob directly inserted into the bolt. This greatly simplifies working the action, and does away with the need of a forward assist. The action can also be manipulated with the rifle shouldered, unlike the AR-15 which requires a charging handle be pulled back right where a shooters face would be.

One point the AR-15 does have over the AR180b is the bolt release. The Armalite does not have one, and this makes shooting single rounds problematic. The AR180b won't be a contender in high power competition any time soon. On the other hand, reloading the chamber after inserting a full magazine is fast and instinctive, and many find it faster than hunting the small lever on the side of the AR-15.


The AR180b does not come with a flash 'suppressor', the ATF having deemed them entirely too evil for normal humans to own. Instead, it has a muzzle break that is reasonably effective. It's machined as part of the barrel, and some folks have a gunsmith replace it with a traditional flash suppressor. Likewise it does not come with a bayonet lug, the ATF having determined that drive by bayonetings are too common to allow the lug.

One unique feature of the AR180 and 180b is the built in proprietary scope base. It's a wedge-like affair welded to the top of the upper receiver. While a little strange, it's extremely effective. An optical sight can be mounted and dismounted easily by hand, returning to zero each time. The downside is availability of scope mounts to fit it. Only Armalite and a few aftermarket specialists make the spring loaded mount it requires.


One company, StorkWerkz, makes a high quality mount that in turn has a standard rail on it. They also sell replacement forearm sets of machined aluminum with multiple rails, just in case the 'robowarrier' image is desired.

My experience with the Armalite AR180b has been a good one. Over the years I've owned a few AR-15 platforms (all Colts) and each has fallen by the wayside, traded or sold. The Armalite is unlikely to suffer that fate, appealing to me more than any of the other black rifles ever did. With an Eotech 512 mounted on a StormWerkz mount, the rifle is boringly easy to shoot well. Hitting the target rapidly is a snap, as the rifle is light and recoil is minimal.


I ran across this rifle by sheer luck, unfired and in the original box for only $575. That is, strangely, the original suggested retail price as well. The rifle now retails for over $850, if you can find one. I consider myself a happy Armalite owner.

19 comments:

Brigid said...

Great - now more things I want to have.

The guys at work were making fun of me. I own two pairs of shoes.

And umpteen guns.

Old NFO said...

Nice review of a forgotten piece of history... Too bad the military didn't listen to Stoner when they had the chance.

Weetabix said...

What calibers does it come in?

Carteach0 said...

.223 only, that I am aware of.

Somerled said...

I'd about forgotten about the AR-180. I used to take a few spins at the range with one a friend owned.

I despise the AR-15's charging handle! It can be hellish to work when there's a failure to chamber that can't be rectified with the bolt assist. The likelihood of having that problem is less with your rig. Thanks for the write-up, carteach0.

Chaz said...

I had an AR180 made by Sterling back in the 1980s and let it go, which I shouldn't have done. It was accurate and dependable, though it did require some work to make the magazines fit. A minor point but a pain. A couple of years ago I got one of the new AR180Bs from Armalite, same as yours, to see how they were working in this version.
Since I was involved in a rather pointed discussion about the relative merits of the direct gas impingement system rifles (the AR) versus the piston systems (FAL, etc.) I took it to the range and put 690 rounds through it as rapidly as I could load several magazines, fire them off, reload and repeat. The gun was hot as hell up front, the parkerizing was a slightly different color from when I started and worried that I might have hurt the barrel. But the bolt carrier was only barely warm and the gun aft of the barrel was cool. I had zero malfs and there was no carbon to speak of inside the receiver when it was all over. That was enough of a demo for me.
Had to let it go, too, but a piston kit for one of my ARs is in the master plan. Thanks for the review, and to pointer to the Stormwerkz site!

mike said...

just busted the front lower pin lugs!!!!!!!!!
Do i have to buy a complete lower????

mike said...

What ammo did you use to get that sweet 4 shot 100yd group??

Carteach0 said...

Mike,

Possibly. I don't really know. It might be repairable, but I can't imagine it will ever be reliable.

How in the world does one break something so tough?

As to the ammunition to fire the group... a hand load found in the Sierra reloading manual.

cma_454 said...

"How in the world does one break something so tough?"

If he means the hinge, that's actually quite common (sadly), and IMHO the major weakness of the AR-180b. You need to use care opening the action for cleaning (letting it fall open is usually the cause of breakage). I've got an idea for repairing it, should Armalite ever not provide a replacement.

BTW, does Armalite still make the AR-180b (I can't find them listed on the Armalite web site, except for replacement parts)?

Carteach0 said...

cma_454,

Sadly, you seem to be correct. Armalite is not listing the AR180b on their site anymore. They seem to be utterly inundated with orders, given the political climate at this time. I suspect they are so swamped that a low volume sideline like the AR180b has been shelved for now.

Anonymous said...

The AR-180B has in fact been shelved for the time being; estimates given from Armalite when contacted by members of the Canadiangunnutz forum put a restart in production sometime in 2010.

In regard to the hinge/pins breaking problem, Armalite treats it as a known issue, and replaces the lower free of cost. Get in touch with Armalite customer service.

Anonymous said...

That's good news, thanks!

Buddy said...

Do you have the Stormworkz mount?...... would you like one? I have an early AR-180B on which the wedge mount was not wielded thoroughly enough to prevent a mounted scope from falling off. I have since picked up one of the MI railed forearms made for it. I have had the wedge repaired twice, but to no avail. I have the extended version of the mount, but it is now surplus to me. I have mounted my EOTech to the railfarm! Email me if you want it...

cma said...

I just got this email from Armalite. It looks like they might not be giving up on the AR-180b.

"The 180B is to be re-designed in 2011 and hopefully re-introduced in
2012. It will not have the polymer lower. No further information is
available at this time.

Tim Rooker
Lead Tech Customer Service Representative
ArmaLite, Inc.
745 South Hanford Street
P.O. Box 299
Geneseo, Il 61254
"AR" stands for ArmaLite"

Stephen D. said...

I have one of these rifles i love it the gas piston is great but since they have discontinued them there lies the problem. I bought mine in 2005 and now the polymer is cracking in the magazine well, you can actually see the release spring. So what if it cracks more i'm stuck with a $ 750.00 club and the lower cannot be replaced bad design in my opinion.

cma said...

Stephen D.,

The last I heard, Armalite is still maintaining an inventory of replacement receivers (if you don't want to wait for the new, non-polymer, replacements).

Anonymous said...

Update Armalite has no replacment polymer lowers, i took mine to the ranger yesterday and the magazine actually fell out twice and i had trouble to get the magazines to saty locked in.And 3 other times the mag dropped and the bolt lock back you can move the mag back and forth with you hand and it's barely hanging in the mag well. So i'll guess i call and raise some hell with them over the issue the guy over repairs, Mario is his name might get back in touch with me in a couple of weeks. Yes i've had issues with him before that 1 year warranty should have been a clue to stay away. But they will repair one way or another and though the rifle is 5 years old i might have put a thousand rounds through it this rifle. So IMO i'd stay away from any Armalite product becasue if there's a problem after you buy their product they don't seem intrested or in a hurry to slove problems.

cma said...

Another update.

I received this, from Armalite:

" Things have changed since my last email response to you. We will be
looking to re-engineer the 180B sometime in the future but for now have
more pressing projects to accomplish. The 2012 date is no longer valid.
No timeline or information on the new 180B is available at this time."