Jumped on the AR9 bandwagon

[ssracer]

I couldn't resist the call any longer and built a 9mm AR.

I decided on a pistol build based on a QC10 Glock small frame lower and MUR upper.
The lower was filled out with a TiN coated milspec FCG, Battle Arms Development selector, Strike Industries enhances pivot and takedown pins and a Magpul MOE SL grip.
I added a Thordsen buffer tube/cheek weld kit and installed a RRA carbine buffer and a Spike's Tactical 9mm heavy buffer.
The bolt is from New Frontier with a BCM CH, and the barrel is an 8" KAK topped off with a Kaw Valley Precision linear comp.
The front end is an SLR 8" SOLO Lite rail ceracoated armorers black by Accurate Armory to better match the flat finish of the receivers.
Attached to that via the Keymod slots are a set of G10 dragon Railscales and a Strike Industries LINK Curved Grip.
Sights are Magpul MBUS Pro.

It is an extremely fun shooter. Feeding, firing and ejecting has all been flawless with 115gr FMJ and JHP ammo. Mags used have been Glock, Magpul, and ETS. I'm going to be going through a lot more 9mm than I used to.

QC10 AR9 Pistol by Sean Dobbins, on Flickr

AR9 Pistol business end by Sean Dobbins, on Flickr

Quarter Circle 10 AR9 Pistol Build by Sean Dobbins, on Flickr

[misfit47]

That's pretty sweet man. They are a lot of fun to play with. Had a few carbines but they used the smg mags. Great training tools for snap shooting and general stress relief.

[kenny256]

That is an amazing build. I really love the look of that pistol.

I have wanted to build one for a while as well.

Sent from my SM-G920V using Tapatalk

[556BlackRifle]

I like it. Been kicking around the idea of building a 9mm and you just gave me another nudge in that direction. Thanks......

[JohnsMyName]

Nice looking build ssracer! I like the handgaurd and hand stop, styling matches well.

[ssracer]

Thanks. The only issue I'm having with it is the last round bolt hold open. It will hold open when the action is worked by hand but not when firing. It's looking like the Spike's ST-9X is just too heavy for it to move enough to clear the bolt catch. Got a spacer coming so I can test with a spare carbine H buffer than I have in the parts bin.

[JohnsMyName]

Just looked up the ST-9x, holy smokes 8oz's! What ammo are you using? Can you try 9mm Nato or a +P variety? I assume you're talking about going to an H1 buffer, seems like a big step back to go from 8oz to 3.7.

[ssracer]

Just been using standard 115gr so far because that's what I have. If I was shooting heavier or higher pressure rounds or suppressed it might work. The test with the H1 is just to verify that mass is my issue. If that works then I'll decide from there what my next step is. I've been in touch with QC10 and they said they typically recommend about 5.5oz for the buffer,

[JohnsMyName]

Just been using standard 115gr so far because that's what I have. If I was shooting heavier or higher pressure rounds or suppressed it might work. The test with the H1 is just to verify that mass is my issue. If that works then I'll decide from there what my next step is. I've been in touch with QC10 and they said they typically recommend about 5.5oz for the buffer,

Cool, sounds like a plan.

[fedupflyer]

I just can't decide whether to go with Glock style mags or Colt style mag.