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Posted: 9/21/2025 12:48:32 AM EDT
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FINALLY received my Atrius as well as my Broad River Tactical SD upper. The Atrius passes the function test and I finally had a chance to take it to the range. Unfortunately I started getting failure to feeds almost right off the bat. With the bolt dropped back, I insert the mag, drop bolt, pull the trigger and first round fires off, second round feeds and fires off and the third is a failure to feed. I tried four magazines (MEAN) with the same results. Now initially I tried the Mean Arms 20 round mag and it worked on semi-auto as well as in forced reset for the first mag and locked back on empty. I then switched to a fully-loaded 30 round mag and that's when the FTF's began to happen. It would also happen in semi-auto. Drop the bolt on the first one, pull the trigger and it goes bang. The second round feeds and fires. Third round, failure to feed, bolt on top of the cartridge from what I could see at a dark indoor range. I switch back to the 20 round mag and it starts doing the same thing. The outliers in my setup are: -Huxwrx Flow 9Ti suppressor -JP SCS buffer system, one tungsten, two stainless weights, with a total weight in the 6.4oz range off the top of my head -Atrius super safety with a Delton mil-spec trigger -Mean Arms Exo Mags (not the conversion kits for 5.56 mags) The rest of the setup: -Broad River complete upper with their SD system -ADM lower -Radial-delayed BCG (CMMG) that comes with the BR upper I also brought along two Unrivaled dead blow buffers, one being the full weight version for a suppressed piston SBR and one being the light version that I run with a titanium BCG in another rifle. Neither one of those changed/improved the function. Ammo was Winchester white box 124 grain, chrono'd at 1050-1080 with the SD setup. I think the box says 1150 or thereabouts for muzzle velocity. I don't think it was the ammo. Anyone using the JP SCS successfully? I originally bought the 5.56 SBR version so it's slightly heavier to begin with. I have a pack of 308 springs which I've not tried yet along with one extra tungsten weight. I also have a few of the Odin adjustable buffers, both the normal and the heavy version with all the weights I'd ever need. So I could swap in a heavier buffer and a normal spring if something like the SCS or Unrivaled dead blow just functionally isn't optimal. Unrivaled is coming out with a heavy version of their dead blow system soon btw and I figured the dead blow function would work well with this setup. To start, I'm leaning towards either the buffer system or the magazines. I've heard the Mean conversion kits tend to be the most reliable but I didn't want to mix up mags and like the fact the Exo's look visibly different. My other train of thought, right or wrong, is the bolt is outrunning the mag and needs a heavier buffer or higher rate spring. But the fact it doesn't work in semi-auto is a mystery. This is my first PCC and I'm looking for input on where to start troubleshooting. Thanks in advance! |
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Does your bolt carrier have a weight inside it? Here are 2 PSA AR9 bolt carriers. Both have weights in them. The weight on the left one has been cut down to work with a Super Safety / FRT.  Image borrowed from this video:  PCC Bolt Mod for #supersafety #pcc #9mm #ar9 #9x19 #bolt This thread has more info. https://www.ar15.com/forums/General/Who-needs-a-MAC-anymore-Regulated-9mm-in-action-/5-2813092/?page=1 |
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I have the 40 round Exomags and when fully loaded, they swell causing malfunctions. I've seen people post the same thing about the lower capacity Endomags. I can't remember if it was the 20 or 30 rounders. I assume the mag is fully loaded when you have FTF at the 3rd round? If so, have you tried loading just 5 rounds where I would hope it wouldn't be swelling and see if it happens again? If not, I would increase the amount of rounds in the mag till it swells. There is a thread on Reddit where someone is measuring the width of the mag with calipers and you can see how bad it is swelling. |
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Originally Posted By drobs: Does your bolt carrier have a weight inside it? https://www.ar15.com/forums/General/Who-needs-a-MAC-anymore-Regulated-9mm-in-action-/5-2813092/?page=1 The BCG is a CMMG radial delayed so no weights. |
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Originally Posted By amphibian: I have the 40 round Exomags and when fully loaded, they swell causing malfunctions. I've seen people post the same thing about the lower capacity Endomags. I can't remember if it was the 20 or 30 rounders. I assume the mag is fully loaded when you have FTF at the 3rd round? If so, have you tried loading just 5 rounds where I would hope it wouldn't be swelling and see if it happens again? If not, I would increase the amount of rounds in the mag till it swells. There is a thread on Reddit where someone is measuring the width of the mag with calipers and you can see how bad it is swelling. Interesting on the swelling! I did try reducing the number of rounds in one of the 30 round mags to see if maybe it was a magazine spring issue or the mags just not "broken in" but had the same results. I'd load five into the 20 round mag and got the same results, FTF on the third round. I'll have a chance to mess with it on Saturday again so I'll try just three in the magazine. Been trying to read as many threads as possible and I'll also check the mag depth and possible swelling issue as it took some effort to get the magazine in and locked in place (30 rounders). I have a 40 round mag as well but didn't try it as I wanted to make sure the rifle worked with the FRT first. I may have to try one of Mean's conversion kits just to see if a PMag does it as well. |
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You have a lot going on in that build. If you're going to properly troubleshoot this and not be chasing your tail, you're going to need to revert back to a basic setup and then add one thing at a time to T&E. The BRT SD upper was designed to run on a standard carbine lower. I would go in this pattern... -- Standard carbine lower (H1 or H2 buffer w/standard carbine spring), standard trigger. -- Change trigger -- Change buffer system Obviously, perform T&E with each change. I'm running PMags with the MEAN insert. Never had a problem except with some downloaded competition handloads (was expected). |
Tom Sawyer.
"If The Rules brought us to this, what use are they?"
"If The Rules brought us to this, what use are they?"
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Originally Posted By tortilla-flats: How is it that you're running a regular suppressor with an SD barrel? I have the same upper and it is not a SD barrel but a SD forward hand guard with a shorter barrel so I use the tri lug and it tucks most of my suppressor under the hand guard for the SD look. If he has a Glock 9mm magazine lower try that or a different lower. Usually when I have issues it is almost always the MEAN or CMMG ends/exomags if he is having semi auto issues. Some lowers like EP9 need a different mag catch from MASON. I know right now he is using a 5.56 lower with conversion mags. He should do what you said and start over....just the upper with a different lower. I have maybe 9-10 CMMG uppers and 5 CMMG lowers...they all function 100%....it's when I put them on a 5.56 lower with CMMG/MEAN end/exo mags I have feeding issues |
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Originally Posted By tortilla-flats: How is it that you're running a regular suppressor with an SD barrel? ETA: Answered. SD look; not SD. It's SD. The barrel is ported and there's a titanium expansion chamber with a HUB interface on the other end. Screw on your suppressor of choice and you have an SD system.      If you need a further breakdown, this is a fun little video to watch:  This PCC Has No Business being THIS good - The CAR-15 SD |
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Originally Posted By Joedirt199: How many rounds on the CMMG RDB? They have a very known problem for ejection issues after 300-500 rds as the ejector spring gets clogged up and loses springyness. Brand new. I have a set of Tubb springs ready to go in and given the fact it bleeds off energy and the rounds are all subsonic, the springs will likely last longer. But I'll report back if there are any issues. |
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Originally Posted By tortilla-flats: You have a lot going on in that build. If you're going to properly troubleshoot this and not be chasing your tail, you're going to need to revert back to a basic setup and then add one thing at a time to T&E. The BRT SD upper was designed to run on a standard carbine lower. I would go in this pattern... -- Standard carbine lower (H1 or H2 buffer w/standard carbine spring), standard trigger. -- Change trigger -- Change buffer system Obviously, perform T&E with each change. I'm running PMags with the MEAN insert. Never had a problem except with some downloaded competition handloads (was expected). On the suppressor, with super semi-auto, one with back pressure is better than one without in terms of running without FTF's. I have an Sig standard baffle can but I'll need an adapter to run it as it's not HUB and won't work with the SD adapter I currently have. I think Ecco makes an adapter to go from HUB to the necessary thread pitch. I'd rather not go there though as the Hux is half the weight and just a great can. I said the same thing to myself but was hoping there was an easy button. It's just strange it does it in semi-auto as well as in super semi-auto mode which leads me to believe it's either buffer or magazine related and not trigger related. I have a few other FRT's I can try out if necessary as well as two Geissele SSA's without a home currently. None the less, your points are noted and I do have a bit of work to do. I guess I know what I'm doing all day on Saturday. At least I find it meditative. |
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Originally Posted By gqllc: I have the same upper and it is not a SD barrel but a SD forward hand guard with a shorter barrel so I use the tri lug and it tucks most of my suppressor under the hand guard for the SD look. If he has a Glock 9mm magazine lower try that or a different lower. Usually when I have issues it is almost always the MEAN or CMMG ends/exomags if he is having semi auto issues. Some lowers like EP9 need a different mag catch from MASON. I know right now he is using a 5.56 lower with conversion mags. He should do what you said and start over....just the upper with a different lower. I have maybe 9-10 CMMG uppers and 5 CMMG lowers...they all function 100%....it's when I put them on a 5.56 lower with CMMG/MEAN end/exo mags I have feeding issues Interesting. I had to pay careful attention to get the mags to seat. I pulled this lower (American Defense Manufacturing) off of a 300 blackout SBR setup since it was already Form 1 registered and I'm using a stock. I'll check out the mag catch and may try the insert version of the MEAN mags while also exploring if there are issues with the mags and my lower. My first run was indoors and it's a dark range. You only get an hour at this place so I was a bit rushed. It's also the only range in town where I can go full super semi and not get booted. |
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Originally Posted By Ape_Factory: It's SD. The barrel is ported and there's a titanium expansion chamber with a HUB interface on the other end. Screw on your suppressor of choice and you have an SD system. https://i.postimg.cc/vZMWnRg9/IMG-8938.jpg https://i.postimg.cc/c4fR61H0/IMG-8943.jpg https://i.postimg.cc/wBwcHWBN/IMG-8931.jpg https://i.postimg.cc/K8Ntr9BW/IMG-8937.jpg https://i.postimg.cc/0NkdTg9x/IMG-8932.jpg If you need a further breakdown, this is a fun little video to watch:  https://www.youtube.com/watch?v=cAG3VaG6N6AWow. You really do have a lot going on with this build. Not sure how anyone's personal experience is going to help with such a unique setup. ETA: My setup CMMG Banshee RDB upper w/new FE, BRT SD barrel, B&T SD suppressor CMMG Mk4 lower w/Geissele SSA-E X trigger (SBR'd); amphibian's A5 buffer setup MEAN inserts in Magpul TMags Before I swapped over to the FE style upper, I was having a lot FTEs. At a pretty low round count too. I think I even have a couple of extra spring sets. ETA2: Keeping an eye on the FRT scene to see which setup I want for this. |
Tom Sawyer.
"If The Rules brought us to this, what use are they?"
"If The Rules brought us to this, what use are they?"
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Originally Posted By gqllc: I have maybe 9-10 CMMG uppers and 5 CMMG lowers...they all function 100%....it's when I put them on a 5.56 lower with CMMG/MEAN end/exo mags I have feeding issues Would this CMMG lower have any compatibility issues with the Broad River upper? I see it incorporates feed ramps. Assuming it takes standard AR15 triggers too? https://cmmg.com/lower-receiver-sub-assm-mk9-9mm-radial-delayed-blowback Edit: Thinking about it, the CMMG lower would likely require the CMMG magazines. |
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Originally Posted By tortilla-flats: Wow. You really do have a lot going on with this build. Not sure how anyone's personal experience is going to help with such a unique setup. Yeah sometimes I do these things....but Micah's ran like a top (watch video) but he used the Rare Breed FRT and MEAN inserts, not the mags. But I believe he had a standard AR15 lower and I think that's what Broad River recommends. |
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Originally Posted By Ape_Factory: Would this CMMG lower have any compatibility issues with the Broad River upper? I see it incorporates feed ramps. Assuming it takes standard AR15 triggers too? https://cmmg.com/lower-receiver-sub-assm-mk9-9mm-radial-delayed-blowback Edit: Thinking about it, the CMMG lower would likely require the CMMG magazines. My CMMG lowers use the Glock mags and I have one that uses the Colt mags as well |
| I talked to Chris at Broad River and basically you'll need the Sprinco yellow spring found HERE plus a 3oz. buffer. I'm going to start with that (and a normal trigger) and then switch over to the FRT and possibly a heavier buffer to slow the cyclic rate down a tad. |
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Originally Posted By Ape_Factory: I talked to Chris at Broad River and basically you'll need the Sprinco yellow spring found HERE plus an H2 buffer. I'm going to start with that (and a normal trigger) and then switch over to the FRT and possibly a heavier buffer. |
Tom Sawyer.
"If The Rules brought us to this, what use are they?"
"If The Rules brought us to this, what use are they?"
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I ordered and received the Sprinco Yellow reduced power spring and I threw in a 3oz. buffer per Chris' recommendation. I did not change out the trigger but did bring all my tools and an extra Geissele I have lying around. Bingo. That worked 100%. Zero failures of any type in semi or super semi. Ran like a top. I really didn't think it cycled too fast but I also didn't do any mag dumps as I was at a range that doesn't allow full auto. Luckily, the 25 yard line was empty and there's a big wall separating it and the 100 yard line. I was able to fire off a few five to 10 round bursts without drawing any attention. It helps that it's so damn quiet. Recoil is extremely light although the recoil impulse is rather strange to what I'm used to. Feels like three small pulses upon firing and two on the return. All the mags worked and I fully loaded one of the 30 round mags which also fed just fine. I should have brought along some HP's, everything I used was round nose FMJ. Now the fun part begins. Developing a supersonic 147 grain load. I'm aiming for 1100fps which should drop down to 1030-1050 or so with the SD system. Using Nas3 cases and it'l be a load for this gun only due to the pressures that'll be required to get the necessary velocity. I have three or four powders I'm going to try out. Federal, Underwood, Buffalo Bore, all make a supersonic 147 grain +P for handguns. So to reiterate, here's a rundown of all the parts used in the build: -Broad River Tactical CAR-15 SD upper (complete) -CMMG radial delayed BCG (included with the BR upper) -PRI M84 Gas Buster charging handle -Huxwrx Flow 9K Ti suppressor -ADM UIC full ambi lower -Sprinco YELLOW reduced power spring (AR15) -3oz. buffer -Atrius Super Selektor with Delton mil-spec trigger (Delton is now defunct) -MEAN Exomags It's a fairly tidy package albeit on the heavy side for what it is. A lot of that extra weight is the titanium SD chamber and the hand guard surround. I'd swap the hand guard out but I know the surround does a great job of keeping the heat contained. I suppose you could go all high end components, like VSeven 2055 upper/lower, all their titanium or aluminum hardware, etc...Smoke Composites hand guard, buffer tube, grip, and a minimalist stock. I have some of that lying around and I may try the Smoke hand guard to see if it rejects heat well enough. Accuracy-wise, at 25 yards, it's pretty much a laser even in SS mode. So no worries there. It'd be nice to get it to work with the Unrivaled dead blow buffer (light version) but I think the spring is too strong. I believe they are going to be coming out with products for the PCC market along with a heavy buffer version which should work well with suppressed FRT SBR's.  |
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Back to the drawing board. No idea why but my next outing, I started getting failure to feed issues where the tip of the cartridge would be jammed upwards with the case head below the bolt. It'd happen on bolt drop or by pulling back the handle and releasing a bit more slowly, albeit inconsistently. I'd get ok feeds on occasion and could get 3-4 rounds before an FTF happened. This was with several different factory cartridges, round nose and HP's. Just bizarre given it worked fine in semi and super semi the last time I had it out. I need to examine everything thoroughly but there's a good chance the mags are sitting too low or even too high. I've also read about the possibility of sharp edges on the leading face of the bolt keeping the cartridge from seating on the bolt face as the bolt moves forward. I do have a bit of uneven wear on the trigger hammer so I'll be looking into that as well. Just want this thing to run as it's so damn quiet. I brought my 300 blackout along and even with ear pro, there's a significant difference in noise.  " />
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I briefly played around with it tonight, hand cycling rounds out of one of the mags and most fed but I'd still get failures to feed. I adjusted the mag release, made it a bit tighter, and that seemed to help a smidge. I watched as the bolt glided over the feed lips, watched as the round was picked up out of the mag, etc...it wasn't a left or right side feed issue as near as I could tell and the bolt didn't seem to be dragging on the feed lips excessively. I did have one bolt hang up where it was past the bolt release but still got caught on something. This was with very slow hand cycling only. I was watching to see if it's a mag related issue, possibly the magazine sitting too high or too low. My first outing, I had issues getting the mags to seat more than once. I also looked over the bolt, looking for sharp edges to see if the round is catching on the bolt as it's trying to seat on the bolt face. I couldn't feel any snags. I did notice a very small dent or nickt on the rim's lip, especially on the ones that got hung up. But that could be from being jammed up like that. One other thing I noticed is when cycling the bolt slowly, pushing the cartridge out of the mag, once it exited the feed lips it would go nose up, pop up, as the mag's spring pushed upwards and the cartridge snapped out of the feed lips. Cycling faster, it was tough to see where the FTF point was or what was different. I may need to film it in slo-mo. |
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Any chance you are near Macon Ga? I just picked up a 9mm RDB bolt and barrel in a trade and have started playing with them with an eye on improving reliability. If you are able....swing by the shop and I'll be happy to take a peek at it....Already developing some ideas that might improve feed especially with regard to the malfunction pic you posted. Rudy |
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Originally Posted By Mad-Machinist: Any chance you are near Macon Ga? I just picked up a 9mm RDB bolt and barrel in a trade and have started playing with them with an eye on improving reliability. If you are able....swing by the shop and I'll be happy to take a peek at it....Already developing some ideas that might improve feed especially with regard to the malfunction pic you posted. Rudy I am not. Well south in Texas. I think I figured it out today. It's the mags. So the Exomag is the stand -alone proprietary 9mm mag by MEAN. They also make the EndoMag which converts 5.56 P-Mags to 9mm. On a whim I ordered the Endomag conversion and installed it moments ago. I then dropped the bolt on a mag full without one single failure to feed. If you compare the two, the Exomag (red follower in the photo below) has a higher floor and a steeper "ramp" just in front of the follower. Additionally the Exomag funnels in towards the center where the Endomag does not. No idea WHY they change the geometry but it is what it is. The cartridge also sits further forward in the Endomag vs. the full Exomag. I'm guessing if you're running an AR lower, you'll want the Endomags. Hitting the range Saturday, weather permitting, to confirm 100%.  " />
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Another range trip and another update. The endomag worked right off the bat but I began to get failure to eject issues which is a known issue with the CMMG bolt face ejector setup. With less than 150 rounds, this is hugely disappointing. I have a set of Tubb springs to go in and will contact CMMG to send out a new set of ejector and extractor springs. The external ejector bolt and upper from CMMG is another $425 not to mention I'd then have to buy all new mags from MEAN to accommodate the external ejector. Anyway...the FTE's were not a regular occurrence. Very erratic ejection pattern, sometimes the cases would fling out at a decent velocity, sometimes they'd dribble out or not at all and I'd get a stovepipe or outright jam (see pics below). I experimented with buffer weight and went from 3.0oz to approximately 2.7oz. That seemed to work somewhat better for feeding overall but on occasion, the bolt would not lock and I'd have to use the forward assist or drop the bolt on the cartridge. I went back to the 3oz buffer and did not mess with the spring which is a soft Sprinco yellow. From there, I started using the Exomags again (remember the Endomags are inserts into 5.56 p-mags) and honestly, they mostly worked. I moved over to a brand new Exomag which I hadn't used yet and began seeing failure to feed issues. So now I believe they need to be broken in both the spring but the feed lips as well as the bolt slides along the outer edges. With all that said, I was able to do some testing on loads and now have a 149 grain load that's technically supersonic but subsonic at about 1045fps out of the ported barrel. This is a PCC-only load using NAS3 steel cases and Vihtavouri N350. Single digit SD's and it's dead on cloverleaf accurate at 25 yards. I went back to testing the mags and my Atrius SS failed. It'd shoot in normal semi-mode but not super semi. I popped the upper open and didn't see any marks or breakage on the Atrius. Haven't had time to dive into it deeper.  
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Originally Posted By Ape_Factory: Another range trip and another update. The endomag worked right off the bat but I began to get failure to eject issues which is a known issue with the CMMG bolt face ejector setup. With less than 150 rounds, this is hugely disappointing. I have a set of Tubb springs to go in and will contact CMMG to send out a new set of ejector and extractor springs. Originally Posted By Ape_Factory: Another range trip and another update. The endomag worked right off the bat but I began to get failure to eject issues which is a known issue with the CMMG bolt face ejector setup. With less than 150 rounds, this is hugely disappointing. I have a set of Tubb springs to go in and will contact CMMG to send out a new set of ejector and extractor springs. Lost cause IMHO. The external ejector bolt and upper from CMMG is another $425 not to mention I'd then have to buy all new mags from MEAN to accommodate the external ejector. Anyway...the FTE's were not a regular occurrence. Very erratic ejection pattern, sometimes the cases would fling out at a decent velocity, sometimes they'd dribble out or not at all and I'd get a stovepipe or outright jam (see pics below). |
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Originally Posted By amphibian: I hate the spring loaded ejector Banshee's..... Documented the issues since 2017. https://c3junkie.com/?page_id=221 Lost cause IMHO. I don't understand why you are saying you need to buy new mags? I use the same ejectorless Endomags / Exomags for the old spring loaded ejector Banshee setups as well as the fixed ejector Banshees. Erratic ejection is common with the spring loaded Banshee...also why they recommend a full length ejection port window and a vertically wider port. Both of which are no longer required with the fixed ejector which has a much more consistent ejection pattern. Yeah I'm now considering the fixed ejector setup and admittedly didn't do enough research before hitting the buy button. A bit of bourbon may have been involved in the process. Maybe Black Friday prices will tempt me but for now I'll continue to test and see where the the current setup leads. I have the Tubb springs and I'll get a few new springs from CMMG as well. I was under the impression I'd need to use the other version of the mag with the ejector. If that's not the case, that is a definite bonus. Mean actually called me TWICE trying to help solve the issue and basically said to get a silver paint pen, cover the feed lips, everything up top, let it all dry for a day. Insert the mags, drop the bolt and see where the bolt makes contact. From there you can dremel/sand down that area so there's no contact and feed errors should stop. They really have amazing customer service especially given the only part I'm using is a relatively inexpensive magazine. |
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I bit the bullet and bought the external ejector upgrade from CMMG. Tired of messing with it and I don't want to fool around with changing springs out and having yet more failures with the more expensive Shell Shock NAS3 cases. Live and learn, do your research before hitting that buy now button! |
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External ejector upper and matching bolt installed. If you make the switch, you WILL need to time the barrel nut so the hand guard rail lines up with the upper receiver rail. So make sure you have barrel nut shims on hand prior. I spent a bunch of time working over each MEAN magazine to make sure there's no drag. I also took the extra step to install some thermal insulation over the titanium expansion SD chamber. I'd hoped to maybe convert to a Smoke Composites carbon hand guard I have lying around unused but the barrel nut is too long. Will need a barrel nut that's short enough to allow the titanium chamber to still screw into the barrel if you want to run a different hand guard. The thermal insulation is Techflex FGN1.00 Insultherm Sleeving 1" and it'll expand enough to slide over suppressors or anything else up to 1.75". It works really well and I use it for a few products I produce for high heat environments in the automobile world. I currently have a non-working-in-super-safety-mode Atrius trigger installed, will likely switch over to another "SS" trigger as I'm tired of f*cking with the Atrius.   |
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Got to the range today and success! I ripped out the Atrius this morning and put in a cheap $100 super safety, push type. I have five MEAN mags total and one 5.56 Magpul converted to 9mm with the MEAN insert. The conversion (Endomag) worked 100%, full mag dump 30 rounds. Three of my MEAN Exomags worked, two need more sanding off the feed lips to eliminate bolt drag. That is absolutely what's causing the misfeeds. In semi-auto, they were all fine. Super semi mode will cause an occasional misfeed. The heat shielding I installed worked really, really well. The hand guard itself is pretty good but it will get borderline hot. I could run my hand along the hand guard and where the tech flex ended, the hand guard increased in temp. If you're planning one of these yourself, just get the barrel, hand guard and SD adapter. Then get the CMMG upper with the external extractor and the matching BCG. It'll run like a top. If you have a ton of p-mags and don't want to mess with possibly tweaking the MEAN Exomags, just get the MEAN Endomag inserts. I didn't have any issue with the Endomag setup with either round nose FMJ or hollow points. Overall it's a very quiet setup and I'm using a high flow suppressor. I'm sure there are other traditional baffle cans that are probably a lot quieter. None the less, I pulled out my ear plug and it was fine. This was with 124 grain Winchester plinking ammo. Super dirty so occasionally I still got a good cloud of gas. When testing the 124 grain supers, to me, they didn't seem any louder. I used Alliant BE-86 and Vihtavouri N340 with Shell Shock NAS3 cases. Hope this helps! 
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Final configuration (we all say that but you know...). I installed the AS Designs ARC-Fire with a Geissele SSA-E, the Doublestar SOCOM stock gen 4 and a Smoke Composites carbon grip I had lying around. Messing around a bit with a digital NV clip on that can sit in front or behind the RDO or as a stand alone as well, haven't quite figured out which mode is best. The Trigger and AS Designs work as promised although you will have to "trim" the Geissele to work and will need the lever blocker as well. But it feels like a Geissele so worth the effort. Lastly, a big FU to Micah for making me spend as much money and exert as much time and energy as I did on a PCC setup. He makes it all seem so easy in the video. I kinda envisioned this as a cheap beater truck gun or an inexpensive HD rifle I could toss around, albeit one that's supremely quiet. One outta two ain't bad I guess. 
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Originally Posted By Ape_Factory: Final configuration (we all say that but you know...). I installed the AS Designs ARC-Fire with a Geissele SSA-E, the Doublestar SOCOM stock gen 4 and a Smoke Composites carbon grip I had lying around. Messing around a bit with a digital NV clip on that can sit in front or behind the RDO or as a stand alone as well, haven't quite figured out which mode is best. The Trigger and AS Designs work as promised although you will have to "trim" the Geissele to work and will need the lever blocker as well. But it feels like a Geissele so worth the effort. Lastly, a big FU to Micah for making me spend as much money and exert as much time and energy as I did on a PCC setup. He makes it all seem so easy in the video. I kinda envisioned this as a cheap beater truck gun or an inexpensive HD rifle I could toss around, albeit one that's supremely quiet. One outta two ain't bad I guess. https://i.postimg.cc/MG3cSb4r/IMG-9382.jpg @Ape_Factory I read the entire thread, and I do not want to miss the details. I would like to replicate your set up, and I have a lot of the pieces around here. Do you mind listing all the parts you are using (again)? I am waiting for BRT to have access to CMMG FE uppers to convert SD-esque suppressor use. It seems like you already have done that. Thank you. |
Words fall from your mouth like shit from ass.
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Here's a full list with links to the major parts: -Broad River Tactical SD Chamber. You'll need to pick whatever model works with your suppressor. I have a HUB suppressor so I use the Bravo series. -Broad River Tactical radial delayed ported barrel -Broad River Tactical hand guard assembly. -Sprinco YELLOW buffer spring. It's part number 25113. -3oz standard buffer -MEAN Arms Endomag. You want the EJECTORLESS version. This converts a Magpul 5.56 P-Mag to 9mm. It's not the full mag but it is the most reliable. -CMMG fixed ejector retrofit kit. Those are all the major parts. You'll want a built out AR15 lower of your choice. |
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Originally Posted By Ape_Factory: Interesting on the swelling! I did try reducing the number of rounds in one of the 30 round mags to see if maybe it was a magazine spring issue or the mags just not "broken in" but had the same results. I'd load five into the 20 round mag and got the same results, FTF on the third round. I'll have a chance to mess with it on Saturday again so I'll try just three in the magazine. Been trying to read as many threads as possible and I'll also check the mag depth and possible swelling issue as it took some effort to get the magazine in and locked in place (30 rounders). I have a 40 round mag as well but didn't try it as I wanted to make sure the rifle worked with the FRT first. I may have to try one of Mean's conversion kits just to see if a PMag does it as well. Yes, my PMags with the Endomag inserts swell too, but maybe not as much as the Exomags. When I load a 30 rounder full, it is noticeably tighter when inserting the mag, but so far it hasn't caused any feed issues. When I first built my upper and started shooting it, I'd get first round FTF when cycling the charging handle from closed bolt or when releasing the BCG if it was locked back, regardless of number of rounds in the mag. After a while, it stopped doing that. Maybe just needed some break in? |
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Just a small update. Mean ghosted me on the exomags. Said I could trim them and if I went too far, they'd replace. Nope. Three emails and zero replies from them. I reluctantly bought the Endomag conversions for my existing PMAGS and those have been reliable. No dragging. Other than that, I just purchased an Aero suppressor-ready M-lok handguard and hoping everything lines up with the existing BAR -style barrel nut. I'd be awesome if Chris simply machined the existing hand guard with M-Lok sized slots (it's a free license) instead of what's on there now. That way if you didn't want to run the shroud, just slide it off and accessorize. I did notice Broadriver now has a "builders" kit for those who want to run a standard hand guard. Thing is, it needs a BAR-style nut and from what I've seen and read, those are as rare as hen's teeth. I've seen a few threads about Aero possibly going out of business but I've not read any of them as I typically don't use their products. I don't think anyone else makes a BAR-style barrel nut as it's Aero proprietary. I don't know if you can simply use a different barrel nut that's 1.25" or shorter as the SD adapter aligns off the barrel nut as you thread it down on the barrel. I've also switched over to a cheap FRT, a push-style safety and it runs great. The Socom stock isn't the lightest but it actually makes the entire package very balanced. Was a good decision. Added a digital day/night vision scope as well that I can even run behind an RDO. About to bulk load a bunch of 147 grain supersonic (yes, super) in Shell Shock NAS3 cases. Off topic, don't buy any bottleneck Shellshock stuff, worthless. Absolutely no QC and measurements from headspace to OAL are all over the place. Super hard to seat primers too and since they're not brass, you're unable to ream/unify primer pockets unless you want to tear up all your tools. The 9mm cases, however, are GTG. They also will not respond to any issues you may have with what you receive. Their customer service is non-existent. Lastly, the cases delivered filthy. It's good for plinking ammo which defeats the purpose of the NAS3 case altogether. |
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Originally Posted By Ape_Factory: Just a small update. Mean ghosted me on the exomags. Said I could trim them and if I went too far, they'd replace. Nope. Three emails and zero replies from them. I reluctantly bought the Endomag conversions for my existing PMAGS and those have been reliable. No dragging. Other than that, I just purchased an Aero suppressor-ready M-lok handguard and hoping everything lines up with the existing BAR -style barrel nut. I'd be awesome if Chris simply machined the existing hand guard with M-Lok sized slots (it's a free license) instead of what's on there now. That way if you didn't want to run the shroud, just slide it off and accessorize. I did notice Broadriver now has a "builders" kit for those who want to run a standard hand guard. Thing is, it needs a BAR-style nut and from what I've seen and read, those are as rare as hen's teeth. I've seen a few threads about Aero possibly going out of business but I've not read any of them as I typically don't use their products. I don't think anyone else makes a BAR-style barrel nut as it's Aero proprietary. I don't know if you can simply use a different barrel nut that's 1.25" or shorter as the SD adapter aligns off the barrel nut as you thread it down on the barrel. I've also switched over to a cheap FRT, a push-style safety and it runs great. The Socom stock isn't the lightest but it actually makes the entire package very balanced. Was a good decision. Added a digital day/night vision scope as well that I can even run behind an RDO. About to bulk load a bunch of 147 grain supersonic (yes, super) in Shell Shock NAS3 cases. Off topic, don't buy any bottleneck Shellshock stuff, worthless. Absolutely no QC and measurements from headspace to OAL are all over the place. Super hard to seat primers too and since they're not brass, you're unable to ream/unify primer pockets unless you want to tear up all your tools. The 9mm cases, however, are GTG. They also will not respond to any issues you may have with what you receive. Their customer service is non-existent. Lastly, the cases delivered filthy. It's good for plinking ammo which defeats the purpose of the NAS3 case altogether. According to that link 80 degrees F, speed of sound is 1138.52 fps. Here in FL, it is like 90 degrees these days. Being adjustable also aids in scenarios where you need more backpressure to aid in cycling and you can kick up the velocity and not go supersonic I built this setup for my teenage son. This setup is so light, it is very close to his airsoft gun in terms of weight. Also very short. I am also very impressed on how quiet this setup is. Suppressor is an old TiRantS that was re-cored by Ecco Machine. What is interesting is that I have a Huxwrx Ca$h9k that is 1/4" longer than this setup and it is super loud compared to the Ecco re-core. The Ecco re-core has baffles closer to the breach side since it was supposed to be used with an external 3 lug mount while the Ca$h9k has space before the blast baffle to accomodate a booster or internal 3 lug so less baffles. I have an Obsidian9 on the way as I want to see how well this setup performs with other popular suppressors.  |
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I’m running the utg pro slim tuckable hand guard and nut on mine it works fine with the adapter. When I first got it going I frt mag dumped 3 different exomags with no problems. The second time I went out they didn’t work at all. I had 3 ejector style endo mags that I cut the ejector off the for the most part work good, I put them together for a mat9 I sold after it broke all the time fuck them scam ass exo mags and also why the fuck do the endo mags cost the same as the exo’s? Makes no sense. I do love this gun, probably my favorite gun with quiet it makes cheap ass 9mm even using a bushwhacker 46. |
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Originally Posted By Smokehouse_83: I had 3 ejector style endo mags that I cut the ejector off the for the most part work good You can see the difference in my link below. https://c3junkie.com/?page_id=598 When initially introduced, MEAN Arms made only one insert for the CMMG RDB and straight blowback variants. If you ordered the CMMG RDB version, they would chop off the ejector on the mag and then sand off the front of the mag as pictured below. However some people were having some reliability issues and MEAN Arms came out with a '2nd gen' version for the CMMG RDB. Picture below illustrates this. 1st Gen on the left and 2nd Gen on the right. Note that the 2nd gen has like 'wings' that go over the feed ramp area which prevent the rounds from jumping over the chamber.  |
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Originally Posted By amphibian: MEAN used to recommend doing that but later changed the design so if you are going to go ejectorless you should get the right ones. They used to swap you out your cut off ones for the ejectorless ones for free. I don't know if they still do that. You can see the difference in my link below. https://c3junkie.com/?page_id=598 When initially introduced, MEAN Arms made only one insert for the CMMG RDB and straight blowback variants. If you ordered the CMMG RDB version, they would chop off the ejector on the mag and then sand off the front of the mag as pictured below. However some people were having some reliability issues and MEAN Arms came out with a '2nd gen' version for the CMMG RDB. Picture below illustrates this. 1st Gen on the left and 2nd Gen on the right. Note that the 2nd gen has like 'wings' that go over the feed ramp area which prevent the rounds from jumping over the chamber. https://c3junkie.com/wp-content/uploads/2020/04/endomog-gen1-vs-gen2-2-1024x656.jpg I definitely have the 2nd gen exo's. I still have two, the 40 rounder and I think a 20 round mag. Both those still work although I don't trust them. |
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Originally Posted By amphibian: I built this setup for my teenage son. This setup is so light, it is very close to his airsoft gun in terms of weight. Also very short. I am also very impressed on how quiet this setup is. Suppressor is an old TiRantS that was re-cored by Ecco Machine. What is interesting is that I have a Huxwrx Ca$h9k that is 1/4" longer than this setup and it is super loud compared to the Ecco re-core. The Ecco re-core has baffles closer to the breach side since it was supposed to be used with an external 3 lug mount while the Ca$h9k has space before the blast baffle to accomodate a booster or internal 3 lug so less baffles. I have an Obsidian9 on the way as I want to see how well this setup performs with other popular suppressors. https://c3junkie.com/wp-content/uploads/2026/04/C3junkie-CMMG-SD.jpg The Ecco re-core also uses standard cone baffles which are almost always going to be more quiet than a flow through (at the muzzle) although the low back pressure suppressors are getting better. The downside is of course substantially more back pressure and gas to the face which may or may not be a problem on your setup. With an FRT, there can be a lot of gas and it can speed up the cycling pretty dramatically. The Hux 9K Ti is better at suppression than the Ca$h and they now have the flow 9K Stiction under the "professional use" tab on the Hux page. https://huxwrx.com/professional-9mm/ It's a hard use can but still under 10oz. I've used standard baffle suppressors on 300 blackout and at the shooter's ear, the flow through stuff is better, not only for gas, but for port pop as the bolt comes back and ejects the case. |
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Originally Posted By Ape_Factory: The Ecco re-core also uses standard cone baffles which are almost always going to be more quiet than a flow through (at the muzzle) although the low back pressure suppressors are getting better. The downside is of course substantially more back pressure and gas to the face which may or may not be a problem on your setup. With an FRT, there can be a lot of gas and it can speed up the cycling pretty dramatically. The Hux 9K Ti is better at suppression than the Ca$h and they now have the flow 9K Stiction under the "professional use" tab on the Hux page. https://huxwrx.com/professional-9mm/ It's a hard use can but still under 10oz. I've used standard baffle suppressors on 300 blackout and at the shooter's ear, the flow through stuff is better, not only for gas, but for port pop as the bolt comes back and ejects the case. Originally Posted By Ape_Factory: Originally Posted By amphibian: I built this setup for my teenage son. This setup is so light, it is very close to his airsoft gun in terms of weight. Also very short. I am also very impressed on how quiet this setup is. Suppressor is an old TiRantS that was re-cored by Ecco Machine. What is interesting is that I have a Huxwrx Ca$h9k that is 1/4" longer than this setup and it is super loud compared to the Ecco re-core. The Ecco re-core has baffles closer to the breach side since it was supposed to be used with an external 3 lug mount while the Ca$h9k has space before the blast baffle to accomodate a booster or internal 3 lug so less baffles. I have an Obsidian9 on the way as I want to see how well this setup performs with other popular suppressors. https://c3junkie.com/wp-content/uploads/2026/04/C3junkie-CMMG-SD.jpg The Ecco re-core also uses standard cone baffles which are almost always going to be more quiet than a flow through (at the muzzle) although the low back pressure suppressors are getting better. The downside is of course substantially more back pressure and gas to the face which may or may not be a problem on your setup. With an FRT, there can be a lot of gas and it can speed up the cycling pretty dramatically. The Hux 9K Ti is better at suppression than the Ca$h and they now have the flow 9K Stiction under the "professional use" tab on the Hux page. https://huxwrx.com/professional-9mm/ It's a hard use can but still under 10oz. I've used standard baffle suppressors on 300 blackout and at the shooter's ear, the flow through stuff is better, not only for gas, but for port pop as the bolt comes back and ejects the case. When he did the re-core, I think he added more baffles. There is no space inside the can to accommodate a booster or internal 3 lug which is perfect for this SD use case. I don't think there are many cans like that as most 9mm cans have a good bit of distance from the blast baffle to accommodate those. One of my friends, says I should make another end cap for my Ca$h9K that doesn't have the the radial ports to see if that makes it sound better. He says it is more for higher pressure. I have people all the time that email about issues with the BRT used in conjunction with the CAT MOB as it is really low back pressure. I know there are some people that have no issues with that combo as well. I haven't gone through the trouble to ask what buffer, spring, buffer tube and ammo all these peoples are running. I'm in FL where FRT's and SS's are illegal but federally registered MG's are OK. Been running full auto M16's for over 20 years. I run this SD setup in full auto. I was just testing with a friend that is a recently retired LE firearms instructor who is also a lefty and sensitive to gas. I also happen to be collaborating with Kynshot on a new hydraulic buffer and he said the Kynshot 5007 already had very little gas in this setup but the new prototype was even better. We also tested my prototype magnetic buffer which we both thought was a tad smoother in full auto but for gas mitigation, the hydrualic was better. Same goes for using a typical carbine buffer or H1 or H2. Gas mitigation was the worst comparing to my magnetic or the hydraulics. With CMMG using the same 55 degree bolt that they use in the bufferless Dissent as the new FE Banshee, I think we need more backpressure for reliability with the SD setup. I also brought out an Octane 9 which is way longer than the Ca$h9k or the Ecco re-core and I was anticipating it to be super quiet but I couldn't tell the difference between it and the Ecco re-core. Both are very quiet. I ordered a Rugged Obsidian9 for testing as I'm curious how it will perform especially in short mode. It is only 4.85" in short mode. |
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The Aero handguard came in and it does indeed work. Bolts right up to the existing BAR-style barrel nut. The screws that come with the aero are a step up from the BR screws. I'm guessing the entire setup removes about 16 oz. of weight. I ordered the 7" but there are other sizes available depending on how much rail length you need. I will say it's a tight fit. Some M-Lok screws might need shortening to work depending on your suppressor's girth. I'm mitigating heat around the titanium SD chamber with Techflex FGN1.00 Insultherm Sleeving. It's 1" in diameter but expands and is good for 1200 Fahrenheit which should be more than enough for 9mm subs. Will take a few photos tomorrow before I head out to the daily grind. |
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