Why Finish One Project When You Can Start Two More

Work progresses on the AR180S Pistol Grip and I am almost happy with the result but in between test prints I do other stuff to keep my mind busy.

How about a 9mm blowback version of the AR180? Sounds like fun! I think this could be an easier way to build a 180 since bolts and carriers are hard to source. I think this bolt could be made with less sophisticated machines and from less expensive steel.

The pistol that got me thinking about this some years back , the 9mm Australian Automatic Arms SAP 9mm.

What do y’all think? AR15 magwell adapter, Slightly modified. (Shown with my long neglected square tube prototype)

3D printed prototype bolt that uses an Uzi extractor and retaining pin.

Trunion design that has the barrel entering from the rear and utilizing a press fit. Although there would be room to fit a cross pin if needed.

What I am thinking it would look like. Maybe a DOE style hang guard retainer and front sight?

Got a 9mm barrel blank from Green Mountain and a chamber reamer from MidwayUSA.

Still have some work to do on the bolt design as I discovered it would not lock the hammer onto the disconnector. I really love being able to print some stuff and test fit it before making stuff out of metal.

Project 2? Selling some stuff to finance all these projects.

I have a very limited supply of Sterling 20 round steel mags for sale. $120 each shipped with tracking. PayPal gladly excepted if you kick in a bit to cover the fees.

Other spare parts as well, just ask for my price list.

Shoot me an email through the contact form if you are interested.


Reader Letter: New Bolt Hold Open for Original AR-180’s

Reader Eric just sent me a message via the contact page and I have to say, it is something I have never considered before. I think it is a great idea. Here is the message he sent me;

From: Eric XXXX
Subject: Can we do a poll?

Message Body:
Hey guys, I was wondering if it was possible to put a poll up on the blog? Reason being, I’ve been communicating with Chuck at Gun Lab about making a bolt catch for original AR18/180’s modified to use mags with standard STANAG followers. I believe this will be a great opportunity for him plus provide us Armalite owners with a much-needed and way-overdue mod for our rifles. Simply put, no more “STANAG or Armalite” mags, just put a slit in a standard STANAG, PMAG or any of the dozens of other mags and it’ll function in the Armalite AND M16/M4/STANAG platform with a simple slit cut in the right-side mag body.
The poll would be simple…
“YES, I would buy this and maybe prepay”
“Yes, I like the idea but want to wait to see how it turns out (price, availability, quality)”
“No, I like being limited to overpriced, rare mags or modifying others to where they can’t be used in any other rifle”
Chuck might be on to one of the best mods to happen to the AR18/180 since it went to market. If we can put up a poll so he can see the interest, I’m sure he’ll move this up his “to do” list.
Thanks and thanks for the site and reviving the AR18/180 legacy!
~Eric, proud owner of a 1982 “widow-maker”


Please comment and let me know what you think of the idea.

Latest Happenings at AR180S.com

I just wanted to touch base with y’all to let you know what has been happening. My new job has kicked into high gear and it has me out of town most weeks and that has the unfortunate side effect of keeping me away from the blog. I am home this week and hope to have an article of substance before I head back out on the road.

A couple weekends ago I found a reasonably priced Mill/Drill on craigslist. Unfortunately it was a 4 hour drive away. I rented a trailer and my wife and I went on an adventure to go pick it up. It had lead a relatively hard life as a drill for an off-road fabrication company and would need a little TLC. What can I say, I am a sucker for a project.

It is a Jet JMD-18 and it is the perfect size for my home shop. Being a round column it will require special consideration to order of operations to reduce the need for raising the head.IMG_0359 IMG_0360

Got it home and it took some doing to get it off the trailer without a cherry picker but we got ‘er done.

IMG_0363 IMG_0365

IMG_0368 IMG_0370

I had originally intended to modify my drill press and use it for small milling jobs so I had purchased a cross slide vise from Harbor Freight but it just didn’t work out. I returned it and picked up a chain fall that allowed me to put this mill on the table.

IMG_0373 IMG_0374

I pulled the spindle apart to get the number off the bearings and put in an order with McMaster Carr. That finished off my weekend as I had to pack and leave town the next morning.


Last weekend the bearings were installed and a run in procedure was initiated.

The head is back together and it runs much quieter.

Cleaning now starts on the table. It stayed locked in one place for years it would seem, so the ways are a little cruddy. A little bit of rust needs to be cleaned off the surface.

Chuck over at the GunLab  keeps cranking out the AR-180B parts and I am hopeful that I will have some kits in my hands soon. Several have emailed me stating their interest and I will be starting up a waiting list. Email me through the contact form and I will put your name on it.





I am also juggling several gun projects myself. I am now on the fence about the 458 SOCOM AR-180B, it may turn into a mid length gas carbine in 5.56. I already have the barrel so it will be cheap but not nearly as cool. I have a Sten MkIII kit that I want to work on after I get the mill up and running. I also want to try my hand an an 80% lower. Not sure which way to go with a buttstock for the AAA SAP. Folder, original, or mill one out of Delrin?

On top of that I have to prepare for a new Advanced Electrical class I am teaching next week and attend a teaching workshop this week.

Brain Overload.



What’s New at AR180S.com

Things have been busy around here and I think it will only get busier. Just the way I like it.

My new job has me out of town during the week but I love to travel and weekends with the family can’t be beat.

Next stop the San Francisco bay area then on to Oklahoma City and Amarillo TX.

The parts lot that I purchased is leading to a potential new project. (Don’t they always)

Thinking about building an AR-180B in .458 SOCOM. Why not, right.

I’m thinking a disapator with carbine length gas and full length handguards in a 16″ barrel.

Mods may have to be done to one of the guide rods and ejection port as the clearance may not be enough to clear the larger case.

Tony Rumore turned down a case head to fit the bolt and snapped this pic to show how little clearance there is.



I have a stripped Bravo upper and bolt carrier group, front sight bases and all the piston parts. Everything to build an upper but the barrel but how boreing would it be to build a stock one. First thought was .300 Blackout but then it struck me. Go Big or go home.


Maybe I can fit the 180C gas block under the hand guards and use a stripped 180B front sight base at the end of the barrel.



I’m going to be moving ahead with this project as funds and time allow. (As I get back to work I gain more of one and less of the other)


By the way I still have a few complete bolt carrier groups available for sale from the parts lot. Pick one up for your next project or as a spare. I don’t have to tell you how hard the bolts are getting to find.


Made up a new flash hider from an original print that I was given access to. (Sorry it’s not anything I can share or publish at this time)

CBC9926B-A93A-4CE1-8C3E-8D5524BF76E9_zpsyzjshkda 1C7DA809-97E9-4CAE-B48E-A0436808C6DB_zpscm1hiuvv

You can see how it differs from the one that I reverse engineered from a picture. I do believe, however that the one I used as an example was not built to the same specs as the one that later made it into production

.AR180S Flash Hider

First AR-18 Carbine

The new to me AAA SAP is begging to be made into an SBR and I am trying to find an original stock.

The rear of the reciever was cut off when it was made as a pistol so some type of adapter would have to be made.

I am also considering the left over Vulcan V18 stock as shown in the teaser pics from my last post.



I still have to get it to the range to test fire it before I even consider sending off for a stamp on this one.

As always I am watching my local craigslist to see if I can find a bigger lathe and possibly a small milling machine.

I am also looking for someone with a Leader T2 MkV that is in southern AZ so I can take some side by side pics and show the differences that were made when AAA took over production.

Thanks for the feedback on the new mail system. It seems to have worked other that the fact that I sent out basically a blank message.

I hope the email you get for this one will be much improved.



AR-180 20 Round Magazines

Today we will be covering the subject of AR-180 20 Round Magazines that were original equipment with your rifle.

All AR-180’s came with two 20 round magazines when sold new but there are several differences in them that we should know about.

They came with magazines that are very similar to AR-15 mags but with a few important differences. They had no cut-out or dimple on the left side and had floor plates that were marked AR-18.

Howa’s came with magazines that were virtually identical but had a different floor plate design.

These are the most common ones found today.

These are generalities and as you will see in the pictures shown below, there are some minor differences even among the 20 round magazines.


Many would consider these magazines interchangeable but upon closer inspection we can see they are different and can be identified as early and late.

The mag on the right has a green/gray color and is quite smooth. The left one is fully gray and has a rougher texture. The one on the right is early and is correct for most Costa Mesa rifles, at least the early ones. It will be referred to as early and the other as late.


In this picture you can also see that the rivets in the early mag are smaller than the the ones used in the late.


Again showing the early mag on the right you can see that the floor plates are different as well. The early plates have a dull finish and the late ones are smooth and shiny. Shown propped on another early magazine.


The early magazines came with a device to block them to 5 rounds. This piece is often missing as this was one of the first things people removed after buying their new weapon.

I have not been able to determine when these early mags were phased out, we may never know. It is possible they shipped with all the Costa Mesa guns and the later ones went with the Sterlings. It is also possible that they were only used early on and the later CM guns used the late mags. More research is needed but the ease with which mags can be swapped around may make this an impossible task.

One piece of evidence that may help is the fact that the Howa mags were identical to these except for the floor plate design.


Here is a Howa next to an early mag. You can plainly see that the rivet is the same and other than the shade being a little off, the color is a close match.




Here the floor plate design changes are easy to see.

To my mind I believe the mags were made by the same company and in the same time period. That would put the manufacture in the mid 60’s to early 70’s.

Lastly we have the easiest to identify, the late Sterling magazine.


The Sterling’s were painted black over parkerization till somewhere around the S20,000 serial number. It is my speculation that they used the gray magazines as well as the black during that time and then used the gray during the remaining run of blue finished guns. I have no evidence to back this up.




Shown hear next to an early mag with a late one on the far right. You will note that the rivets are the same as the late mag.



The floor plate is also smooth and shiny like the late mag but features a white color fill in the lettering.


A better view of the different floor plate designs and finishes.


All of these mags used a black plastic follower that has a cut-out for the bolt hold open at the rear.

In order of rarity and application;

Late gray magazine, Late Costa Mesa? and Sterling. Overwhelmingly the most common.

Black Sterling Magazine. Not common

Early Costa Mesa magazine. Not common

Howa Magazine. Not common

All of the uncommon mags will be hard to find but many of them will be lumped in for sale with the common gray mags and will not be sold at a premium. This is not true for the Howa mags however as they are easily identified.

I would like to say thank you to Chuck at GunLab.net for the suggestion of this article and the load of original source material he is sending me to further my research and to bring you more articles in the future. Go check out his site, it is a wealth of information.