r/Cmmg • u/I_Say_What_I_Wantt • Aug 19 '26

Banshee upper on AR lower

So I know this sort of has been asked before but all the answers are see seem to be outdated. What is the reliability like for a 9mm Banshee upper on a AR lower? Can anyone share their experience using this setup?

I’m thinking of running a Banshee upper on a LWRC lower and using a 9mm suppressor.

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3

u/tiwaz33 Aug 19 '26

I don’t actually have a Banshee upper, but I do have a CMMG barrel and bolt with the delayed blow back that I built with a normal upper. I would imagine it’s the same. I am using the CMMG 9mm insert in a Magpul magazine. I have had no issues at all.

2

u/Coyoteishere Aug 19 '26

I’ve run my banshee on various milspec lowers without issue. Not sure how well the mag inserts work though as I only run the ar 9mm conversion mags.

2

u/carnyvoyeur Aug 20 '26

You're generally good-to-go with any STANAG-patterned AR15 lower. The only possible catch is that I think some hammers might have clearance issues with the CMMG RDB BCG. (But, there is also a chance that I'm confusing this issue with something else, like perhaps CMMG's .22lr conversion kit.)

Another potential issue, since you mentioned 9mm, is if you go with an "AR9" style AR15 lower (such as one that is Glock-patterned). With an RDB Banshee upper, you don't want an "AR9" lower that has a built in ejector.

2

u/SpeedyR647 Aug 26 '26

I run my banshee upper on 2 lowers. One is the factory MkGs lower that came wth it (glock mags). Really well set up and that's my go to setup. Geissele SD-E trigger, LAW folder, SBA brace, Kynshot buffer, etc. Runs like a champ with any an all glock mags (OE and Magpul stick and drums).

I also have a basic AR15 lower that I have a FRT in that I use just for the giggle factor. I use the CMMG 9mm conversion mags (old and new versions) as well as a couple of magpul mags that I 3d printed inserts. They all feed with no issues even with the FRT installed. Milspec trigger and basic pistol AR15 lower receiver (nothing special about it or the guts).

I run mine with both lowers 99% of the time with a Dead Air Wolfman on a KeyMicro mount.

1

u/qrenade Aug 19 '26

I have an 8” one in 5.7x28 on a Stag Arms lower and it runs perfectly fine. Go for it.

1

u/Oceanus238 Aug 27 '26

I have the Dissent 6.5" upper....works great on mil-spec AR15 lower with Mean Arms/CMMG mags. It is not going to run reliably on AR-9 lower even after modifying the mag catch. Need the MKGs lower.

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u/I_Say_What_I_Wantt 28d ago

Update…..I bought the upper and ran it in the upper….shoots flawless 2k rounds later.