You asked for it. And it has arrived. I released the V1.0 AR-9 Super Lower a few days ago. Here are the details.
My goal for the project was to have a 9 MM lower that would work with Glock magazines, use as many standard AR-15 parts as possible, and feature a last round bolt hold open. I have met two of those goals so far. The last round bolt hold open still remains elusive.
The V1.0 AR-9 is basically a V3.0 Super AR-15 Lower with a redesigned front end. The front pin plates on the AR-9 are the same as on the AR-15.
The only non AR-15 parts in this AR-9 lower that can not be 3D printed are, the 3/32″ roll pin used to secure the mag catch lever, and the heavy buffer needed for reliable operation.
If you want to buy all the parts you need to complete the AR-9 lower, all you will need is this pin, an AR-15 Combo Kit, and the KAK heavy 9 MM buffer.
Both the magazine catch and ejector are 3D printed. Yes, you read that right, the ejector is also 3D printed! This saves us the trouble of having to source a third party ejector.
The ejector is 3D printed separately and simply presses into the lower body. The edge of the upper is what holds the ejector in place. It is as secure as screwing it in, but without needing any fasteners.
I have had some concern as to the longevity of this plastic ejector, since almost all other ejectors are made from steel. But so far the Overture Easy Nylon ejector, after more then two hundred rounds of 9mm, shows no signs of wearing out!
To date I have fired 224 rounds of 115 Grain FMJ ammunition without a single failure or malfunction! It took awhile getting here though! Below can be seen some of the prototypes that where needed to get all the right parts into the right places. The magazine position proved to be critical for proper feeding.
I assembled the upper using a KAK AR-9 Bolt and Barrel. The upper is a simple mil-spec stripped upper. I found it very important to use the right buffer mass, My first test ended with a case separation that I believe was partly caused by a light carbine buffer. I am now using a KAK heavy extended AR-9 buffer.
Here you can see the aftermath of the case separation. Fortunately the lower was the only part harmed by the accident. The overly light buffer allowed the bolt to open too quickly while there was still tremendous pressure in the shell casing. Once the shell was no longer supported by the chamber walls, it ruptured under the force. I have not had a single problem since moving to the heavy eight ounce buffer.
The mag catch is 3D printed and attaches to the lower using the steel roll pin. It is powered by the very same spring that powers the AR-15 mag catch. Which is very convenient.
Here you can see the print orientation of the two small parts. I think that a Nylon is perfect for the ejector. As Nylons have excellent wear resistance. However, the Nylon mag catch on my latest AR-9 print has bent out under the continuous force of the spring. It still works, but I think a Carbon Fiber Nylon or Polycarbonate would be a better option.
So you want to print one? First you will need to head over to the Downloads page and grab the files. Then you will have to source the parts. I will start selling complete AR-9 Combo Kits once I get all of the parts. But for now you will have to order a few different items. In addition to the AR-15 Combo Kit you will need a 3/32″ x 1″ roll pin and a heavy buffer. I recommend the KAK extended 9 MM buffer : https://www.kakindustry.com/ar15-9mm-buffer-long
For the upper you have lots of option, But I, once again, recommend KAK equipment.
This is the bolt I use: https://www.kakindustry.com/kak-9mm-enhanced-bcg
And here is the barrel: https://www.kakindustry.com/ar-15-parts/upper-parts/barrels/contract-9mm-11-inch-melonite-barrel You can of course use other barrel lengths.
Any AR-15 stripped upper and handguard will work with the above equipment.
Below I have imbedded my latest video testing the AR-9 lower.
That’s all for today!!