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6/16/2026 10:04:00 PM EDT
Several years back I caught the PCC bug and built a little braced CMMG RDB pistol. I took it for a range trip and absolutely loved it. I took it for a second range trip and the ejector spring nightmare began.

In the end I found that it had to be almost immaculately clean, well lubed, and the ejector spring had to have less than 400 rounds on it. If those 3 conditions weren't met, it wouldn't run. It went back to CMMG and they replaced the bolt and barrel, to no avail. It went back again and got another new bolt and barrel, and this time I just sold it.

Now I understand that they have gone to a fixed ejector, which would have solved all of my problems.

Recently I started hearing about the Broad River Tactical Uppers and I love the idea, but I don't really want something where it MUST be fired suppressed, and the adapter and suppressor combo sounds heavy, so those might not be a great fit for me. Subsonic ammo is no biggie for me as I have a great load that really doesn't cost any more than loading regular 124s.

So then I discovered that c3junkie/amphibian is now selling uppers with good barrels and one of his with a tri-lug sounds like just the ticket for me. Throw that onto my SBR lower with A5 tube and CMC 2.5# trigger,  swap in a neverwear spring and an RB5007, grab some endomag conversions, and it sounds like I would have what I wanted a few years back.

What do you think? Should I go for it, or will I regret it? Feel free to talk me out of it or share your bad experiences with recent RDB guns. Thanks!
6/16/2026 10:38:42 PM EDT
[#1]
I don't know about your bad luck but mine has 5k on it by now maybe full auto. Clean it every year. Mostly run suppressed full auto. Most times I take it out it has 0 jams.
6/16/2026 11:26:06 PM EDT
[Last Edit: willi3d][Edited] [#2]
I have an old 9mm Guard (what 8” Banshees used to be called) and never had any problem with it.  Earlier this year, I used the FE conversion to upgrade it for piece of mind and it still runs fine.  Almost all of my shooting is suppressed via a trilug mount.  Also have a 10mm Banshee that runs fine.  I wouldn’t hesitate to buy another CMMG RDB gun.



7/22/2026 7:17:04 AM EDT
[#3]
Zero issues with mine in 9mm and 45ACP.
7/23/2026 7:13:43 PM EDT
[#4]
I do love my 45 caliber MKg.  Runs great, always suppressed, and is one of the few guns I can call a "laser beam" under 120 yards mind you.

Long ago I lost count of how many rounds have gone through it exactly but I know for sure I'm well into 5,000 now.  Still no issues.
7/24/2026 6:20:44 AM EDT
[#5]
Of course I'm biased but that is all I run these days.  If you have FA or FRT / SS, there is no other SMG on this planet that can be tuned to have a slow cyclic rate AND have low reciprocating mass.  I go over my history and current status with the platform here: https://c3junkie.com/?page_id=3168   However, tuning is NOT required.  I'm just after a slow cyclic rate and low mass.  If you don't care about that, you don't need to lighten the carrier like I'm doing or messing with experimental magnetic buffers etc...
Regarding the Neverwear Warthog spring, note that later batches are too tight.  I reached out to Neverwear and had my own made to my specs that I have on my site.  Specifically larger ID to accommodate the RB5007 as well as the upcoming RB5000A5 that I collaborated with Kynshot on.

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