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Posted: 4/15/2026 4:31:17 PM EDT
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Are these in production? How good or bad are they? Shopping against the DD 9mm SBR. TIA, Sid |
Yes, absolutely still in production. Available in Banshee (buffer tube) and Dissent (no buffer tube) styles. The newer ones are FE (fixed ejector) models which solved the issues with the plunger type ejectors of older versions. I have an old MkGs Guard (what they were called before the Bansee) that I upgraded to at FE upper, and enjoy it a lot. I also have a DD PCC. It’s nice, but I think I like the CMMG a little better for the shooting experience, especially suppressed. Less gassy, softer recoil, and easier to tune. |
| Can you elaborate on the old vs. new style? I've had a few FTF with my older Banshee. Can it be upgraded? |
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Originally Posted By WWolfe: Can you elaborate on the old vs. new style? I've had a few FTF with my older Banshee. Can it be upgraded? The original 9mm RDBs have an AR style bolt with the plunger ejector in the bolt face. The new ones, called FE, have a fixed ejector tab screwed into the side of the upper, and a new bolt and carrier with a slot cut into them to clear the ejector tab. CMMG sells a FE retrofit kit with a new upper, bolt and carrier. That’s what I did, and just reused my original barrel and handguard. Some people have said they’ve gotten it for free if they complain enough. https://cmmg.com/fixed-ejector-retrofit-kit-9mm |
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Originally Posted By WWolfe: Can you elaborate on the old vs. new style? I've had a few FTF with my older Banshee. Can it be upgraded? Bolt 1 is from the older spring loaded ejector Banshee showing it uses a 50 degree bolt. The 9mm Dissent which finally had a fixed ejector came out in early 2023 which is bolt #2. Notice how the cam pin hole has been moved more to the rear to accommodate the slot required to clear the fixed ejector or the bolt will crack after XX amount of rounds. IME about 20K rounds if you were crazy enough to retrofit a custom fixed ejector in the old CMMG spring loaded ejectors.  So from 2023 to early 2025, I was modifying the Dissent BCG's to work with the buffer tube and run them in full auto since a Dissent doesn't have anything to trip the autosear. Notice at the bottom how I had to mill a new cam pin relief in the upper for this to work. CMMG also wouldn't sell me their ejectors used in the Dissent so I had to buy APC9 ejectors and mill them out to fit.  Then in Feb 2025, CMMG finally released the FE Banshee's and I have been using the Retrofit Kits to build them out using my barrels as their barrels are known to have issues like I have documented here: https://c3junkie.com/?page_id=1882 This recent thread is discussing someone's dissatisfaction with unburnt powder coming from his action and I am suspecting it is the barrel but it is hard to say without seeing it first hand: https://www.ar15.com/forums/Armory/New-CMMG-Banshee-MkGs-A-few-FTFeeds/48-562010/ CMMG customer support gave him a generic answer. Like I mentioned in that thread, when I had a bad barrel, they wouldn't anything for me either. I had to buy another BCG / BBL combo and use a high speed camera to show the difference is extraction and then they finally replaced my first barrel as it had excessive headspacing. I got so fed up, I stopped using their barrels, started converting straight blowback barrels for the CMMG system and getting a run of my own made. |
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Originally Posted By sidpost: Are these in production? How good or bad are they? Shopping against the DD 9mm SBR. TIA, Sid I have a love / hate relationship with CMMG. I have been running them since they came out in 2017 as IMHO, they are the best option for a full auto on a RR as I have documented here: https://c3junkie.com/?page_id=361 There is no other 9mm SMG on the planet that can run in range of 600 RPM AND have low reciprocating mass. Running this slow allows you to leave the selector on FA and pull a SINGLE round burst as well double, triple or quadruple as I demonstrate in the video below. I'm in FL where FRT's / SS's are illegal but I have a lot of customers that use those devices and they are drop in with the CMMG RDB.  C3Junkie custom 9mm Banshee 12-2025 The only caveat with the SS I have documented below. I don't know why these particular SS's are made to be so much more narrow than a milspec autosear. I really like the idea of the AZ Regulator or maybe get a Partisan Disruptor if you hate Rare Breed. Another point is that in the video above I am using a magnetic buffer and someone posted that the magnetic buffer magnetizes the carrier which then attracts the SS and causes issues. So that is another reason I would go with the AZ Regulator or Partisan Disrupter as I do not think they are affected by the magnets.  |
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