Quarter Circle 10 – QC5 Receiver set for MP5 9 mm magazines

Eric B
by Eric B

I’m not new to 9×19 mm carbine shooting, but I only shot my first match with a 9 mm “rifle” recently.

If you can, you should try Pistol Caliber Carbine (PCC) competition because it’s great fun.

In terms of choosing a Pistol Carbine there are a few roads to go.

AR9 is one, but I have a really, really hard time with the looks of the carbines that use the Glock magazines, or those that run the AR15 magwell. It just doesn’t look right.

QuarterCircle10 now have a receiver set called the QC5. It’s engineered for HK MP5 9 mm magazines only. The lower and the rear charging upper are milled billet 7075-T6 Aluminum, so the looks are good.

Unfortunately there are no pictures of a complete build I can use, but you can get an idea from TBF’s previous article from SHOT Show. However it looks like QC10 went with another solution for the side charge than previously displayed?

QC5 Description:

  • QC10 Stripped QC5 Lower Receiver with proprietary parts

  • Accepts mil-spec receiver extension (buffer tube)

  • QC5 Rear Charging Upper Receiver

  • No charging handle

  • Engineered for 9x19mm MP5 magazines

  • Both receivers are milled billet 7075-T6 Aluminum

  • Type III Hard Coat Anodizing

  • No Lower Parts Kit installed
  • Made for the AR Platform – Not Modified

The QC5 Receiver set will set you back $540 and you can find more details at QC10.

QC also released a “new” product. They don’t make it, but they QC10-branded Radian Weapons’ Ambidextrous Charging Handle for those who want to shop everything in one place, with one brand.

Eric B
Eric B

Ex-Arctic Ranger. Competitive practical shooter and hunter with a European focus. Always ready to increase my collection of modern semi-automatics, optics, thermals and suppressors. TCCC Certified. Occasionaly seen in a 6x6 Bug Out Vehicle, always with a big smile.

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2 of 45 comments
  • D s D s on Oct 16, 2017

    Why can't Ruger 5.56 come out with 9mm. Upper for the AR 5.56

  • Tom Tom on Oct 17, 2017

    Doesn't this make it more look like an MPX knockoff? If I am building a 9mm lower I would want the glock mag lower. Glock mags are everywhere. I would imagine MP5 mags are much more expensive as anything HK is $$++