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Posted: 2/27/2023 11:04:20 AM EDT
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Seems like the Mean Arms Bearing Delay upper is getting some press. CMMG's radial delay blowback has been around for a bit but with apparent teething issues surrounding broken Then there's the Scheel's Roller Delayed Buffer which allows you to use your existing upper and just swap in the tunable buffer. Are these designed to still use the heavier BB bolt, or are they designed to work with a lighter BB bolt or other setup? Finally, there's DI, but 9mm DI seems to be more finicky than .45ACP based on the very limited research I've done. Love my RMWX DI 45ACP upper that runs with GG mags, but I don't see as much on DI 9mm. I have two blowback setups, a DDLES Glock mag lower with an 8.5" Davidson Defense upper and a KP-15 polymer lower with a Hahn magblock for Colt mags wearing a 7.5" Model 1 Sales upper. Both use an H3 buffer and standard carbine spring. Both are shot suppressed 100% of the time with 147gr subsonic handloads. I've been wanting to get a lighter recoiling 9mm AR just because. So, what's the go-to 9mm AR system that will run on my existing DDLES Glock mag lower and/or with Colt mags with the magblock on a standard lower while dropping the reciprocating mass and recoil? |
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I can’t speak to the first two other than the fact CMMG seems to have zero presence in the competitive shooting world as far as PCC goes, which is strange. I’ve looked into them but quite frankly their website, information and parts availability is somewhat lacking. I use the Scheels roller delay and absolutely love it. Right now I have a full weight bolt in my USPSA gun at 135pf and removed the weight in my Steel Challenge gun at 115pf. I still need to play around with tuning but I’m pretty certain I can remove the weight in my USPSA gun. |
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I put my reservation in and hope to have some feedback whenever I get mine. CMMG's radial delay blowback has been around for a bit but with apparent teething issues surrounding broken extractors. Then there's the Scheel's Roller Delayed Buffer which allows you to use your existing upper and just swap in the tunable buffer. Are these designed to still use the heavier BB bolt, or are they designed to work with a lighter BB bolt or other setup? Finally, there's DI, but 9mm DI seems to be more finicky than .45ACP based on the very limited research I've done. Love my RMWX DI 45ACP upper that runs with GG mags, but I don't see as much on DI 9mm. I have two blowback setups, a DDLES Glock mag lower with an 8.5" Davidson Defense upper and a KP-15 polymer lower with a Hahn magblock for Colt mags wearing a 7.5" Model 1 Sales upper. Both use an H3 buffer and standard carbine spring. Both are shot suppressed 100% of the time with 147gr subsonic handloads. I've been wanting to get a lighter recoiling 9mm AR just because. So, what's the go-to 9mm AR system that will run on my existing DDLES Glock mag lower and/or with Colt mags with the magblock on a standard lower while dropping the reciprocating mass and recoil? It took a lot of tuning and a custom fixed ejector to get it to where I mine is right now. https://c3junkie.com/?page_id=164 Most people are not willing to go through the lengths I did. Even at the point I am at now with the CMMG RDB, I would like to reduce the reciprocating mass a bit more but find that if I do that, no combination I have tried still works in full auto doing that. I am hoping that the MEAN Arms will be able to be tuned to what I am looking for but will just have to wait and see. |
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Quoted: I can’t speak to the first two other than the fact CMMG seems to have zero presence in the competitive shooting world as far as PCC goes, which is strange. I’ve looked into them but quite frankly their website, information and parts availability is somewhat lacking. I use the Scheels roller delay and absolutely love it. Right now I have a full weight bolt in my USPSA gun at 135pf and removed the weight in my Steel Challenge gun at 115pf. I still need to play around with tuning but I’m pretty certain I can remove the weight in my USPSA gun. I was kinda thinking the same ref CMMG seeming to be a novel solution, but not really seeing them at matches. Being able to knock out the roll pin and drop the weight in the ass end of the blowback 9mm bolt would seem like a great way to drop reciprocating weight. My 147gr loads are 150-155pf from the PCCs and 145pf from a G17, so not screamers by any stretch. Wonder if I'd be able to drop the carrier weight and run an H2 with the Scheels.... |
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Quoted: I was kinda thinking the same ref CMMG seeming to be a novel solution, but not really seeing them at matches. Being able to knock out the roll pin and drop the weight in the ass end of the blowback 9mm bolt would seem like a great way to drop reciprocating weight. My 147gr loads are 150-155pf from the PCCs and 145pf from a G17, so not screamers by any stretch. Wonder if I'd be able to drop the carrier weight and run an H2 with the Scheels.... The Scheels replaces the buffer with their own buffer which has the roller locking mechanism in it, so you wouldn’t be able to run an H2. |
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Quoted: ... Finally, there's DI, but 9mm DI seems to be more finicky than .45ACP based on the very limited research I've done. Love my RMWX DI 45ACP upper that runs with GG mags, but I don't see as much on DI 9mm... I do not have direct experience with a DI 9mm action. It is my understanding that it can be done, but if you shoot commercially available ammunition, they tend to get the gas path dirty (and clogged up) fairly quickly. I know that some folks are using a DI 9mm carbine, but they handload their ammunition with special powders that shoot a lot cleaner. Still, they have to clean their gun really frequently, but fortunately the gas path is really short, so it's not too difficult to clean if you have the right tools. A friend I used to see at the range had one, and told me all of this and that convinced me to go with a simple blowback system. My blowback 9mm SBR is a heavy pig compared to my 5.56 SBR, but still enjoyable to shoot (but not to lug around in the woods). Having a locked breach so that you can lighten the reciprocating components would be very nice, so I'm also looking at the alternatives available today compared to back when I built my 9mm SBR in 2013. |
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Quoted: The Scheels replaces the buffer with their own buffer which has the roller locking mechanism in it, so you wouldn’t be able to run an H2. Quoted: Quoted: I was kinda thinking the same ref CMMG seeming to be a novel solution, but not really seeing them at matches. Being able to knock out the roll pin and drop the weight in the ass end of the blowback 9mm bolt would seem like a great way to drop reciprocating weight. My 147gr loads are 150-155pf from the PCCs and 145pf from a G17, so not screamers by any stretch. Wonder if I'd be able to drop the carrier weight and run an H2 with the Scheels.... The Scheels replaces the buffer with their own buffer which has the roller locking mechanism in it, so you wouldn’t be able to run an H2. Haha, of course it does. Had CMMG on the brain when I typed that. |
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Quoted: nope just the old school blowback. there are also some MBX guns which are very nice. Quoted: Quoted: When you say JP, you mean their roller-delayed JP-5? nope just the old school blowback. there are also some MBX guns which are very nice. Yeah, direct BB works, but I’d like something with a little less recoil and weight as my wife wants to get back into PPC matches and dropping the recoil would help her as well. |
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Quoted: Yeah, direct BB works, but I’d like something with a little less recoil and weight as my wife wants to get back into PPC matches and dropping the recoil would help her as well. Quoted: Quoted: Quoted: When you say JP, you mean their roller-delayed JP-5? nope just the old school blowback. there are also some MBX guns which are very nice. Yeah, direct BB works, but I’d like something with a little less recoil and weight as my wife wants to get back into PPC matches and dropping the recoil would help her as well. The whole key is to handload. A 9mm only needs to go 1100 FPS with 115 grain bullet. A watered down 9mm load is super soft to shoot. This will do way way more for your goal rather than an operating system. I believe federal sells some match pcc laods for this reason If you don't load your own. A pcc barrel adds about 200 FPS to a round vs a pistol barrel. Don't use factory ammo is the key with pcc. 147 grain are even softer. click here |
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Quoted: The whole key is to handload. A 9mm only needs to go 1100 FPS with 115 grain bullet. A watered down 9mm load is super soft to shoot. This will do way way more for your goal rather than an operating system. I believe federal sells some match pcc laods for this reason If you don't load your own. A pcc barrel adds about 200 FPS to a round vs a pistol barrel. Don't use factory ammo is the key with pcc. 147 grain are even softer. click here There’s no way in hell I’d dance that close to the PF floor as 126. Besides, you really can’t tell the difference on the clock between that and 135 so best to be on the safe side. |
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Quoted: There’s no way in hell I’d dance that close to the PF floor as 126. Besides, you really can’t tell the difference on the clock between that and 135 so best to be on the safe side. Quoted: Quoted: The whole key is to handload. A 9mm only needs to go 1100 FPS with 115 grain bullet. A watered down 9mm load is super soft to shoot. This will do way way more for your goal rather than an operating system. I believe federal sells some match pcc laods for this reason If you don't load your own. A pcc barrel adds about 200 FPS to a round vs a pistol barrel. Don't use factory ammo is the key with pcc. 147 grain are even softer. click here There’s no way in hell I’d dance that close to the PF floor as 126. Besides, you really can’t tell the difference on the clock between that and 135 so best to be on the safe side. I also only load one 147gr load. They’re 980fps in my G17 and ~1050fps in the 7.5” and 8.5” PCCs. If the MEAN upper works I’d probably go with a 4.5” barrel. I could tailor loads to each weapon, but prefer to just load a thousand when I need more and ensure everything that shoots 9mm uses the same load, save for carry guns which get 147gr XTPs that are loaded to the same POI/POA and velocity as the plated 147gr blasting ammo. This lets me practice with plated handloads and save the more expensive XTPs for carry. |
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Quoted: I also only load one 147gr load. They're 980fps in my G17 and ~1050fps in the 7.5" and 8.5" PCCs. If the MEAN upper works I'd probably go with a 4.5" barrel. I could tailor loads to each weapon, but prefer to just load a thousand when I need more and ensure everything that shoots 9mm uses the same load, It is almost identical in length and is less then 1 oz heavier than my suppressed 5.56 setup above with of course identical manual of arms.  |
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Quoted: I too only load one 147Gr load. I load for the longest barrel that I run suppressed and that is a ~9" 3 lugged UZI SMG barrel to around 1000 FPS and all my other SMG's and pistols run that load. So I've opted for the 7.5" MEAN Arms upper. Been running the 8" CMMG RDB's for some time and I like that length as it gives me a good amount of rail space. It is almost identical in length and is less then 1 oz heavier than my suppressed 5.56 setup above with of course identical manual of arms. https://c3junkie.com/wp-content/uploads/2020/04/CMMG-RDB-vs-12_5_BrevisUII-1024x479.jpg Quoted: Quoted: I also only load one 147gr load. They're 980fps in my G17 and ~1050fps in the 7.5" and 8.5" PCCs. If the MEAN upper works I'd probably go with a 4.5" barrel. I could tailor loads to each weapon, but prefer to just load a thousand when I need more and ensure everything that shoots 9mm uses the same load, It is almost identical in length and is less then 1 oz heavier than my suppressed 5.56 setup above with of course identical manual of arms. https://c3junkie.com/wp-content/uploads/2020/04/CMMG-RDB-vs-12_5_BrevisUII-1024x479.jpg Rail space is a concern as one of my 9mm ARs wears an IR laser/illuminator for night matches. Maybe the 7.5" would be the better call as I don't like nesting a suppressor under the handguard. |
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Within the last year I switched from an old school Olympic Arms straight blowback setup to the RDB CMMG Banshee. I really, really like it. Only problem I had was right out of the box. Think there was a burr on the trigger/hammer interface. Once I got past that, she has been smooth. Customer support from CMMG was top notch, they sent a free replacement trigger group without hesitation. Pros - doesn’t get as dirty as straight blowback for same number of rounds Cons - ain’t cheap I now run the banshee at our IDPA and steel challenge matches. I am as fast with the banshee as I am with my rimfire rifle (that has the same optic and trigger). Yes, I handload and you should, too. No, you won’t save money in 9mm but you will be able to tailor your load. The banshee eats my hand loads in 115, 124, 135, 147, and 165 grain offerings (mostly with W-231) without complaint. |
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Look up the thread on this sub forum "gentle recoil blowback AR9" or something to that effect. Its blowback, but uses a combination of parts that makes it feel like an MP5 push than a straight blowback punch. Just right carbine extended buffer tube Flat wire spring Kynshot 9mm heavy hydraulic buffer 2x kynshot buffer weights (or I made my own single weight from steel round bar cuz I has a lathe) Standard weighted blowback bolt The total reciprocating mass is in the 28oz range, you need the extended tube for the extra 1.5" of weight added between bolt and buffer. It really does feel like a totally different gun. Zero bolt bounce too. |
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Quoted: Look up the thread on this sub forum "gentle recoil blowback AR9" or something to that effect. Its blowback, but uses a combination of parts that makes it feel like an MP5 push than a straight blowback punch. Just right carbine extended buffer tube Flat wire spring Kynshot 9mm heavy hydraulic buffer 2x kynshot buffer weights (or I made my own single weight from steel round bar cuz I has a lathe) Standard weighted blowback bolt The total reciprocating mass is in the 28oz range, you need the extended tube for the extra 1.5" of weight added between bolt and buffer. It really does feel like a totally different gun. Zero bolt bounce too. Quoted: Look up the thread on this sub forum "gentle recoil blowback AR9" or something to that effect. Its blowback, but uses a combination of parts that makes it feel like an MP5 push than a straight blowback punch. Just right carbine extended buffer tube Flat wire spring Kynshot 9mm heavy hydraulic buffer 2x kynshot buffer weights (or I made my own single weight from steel round bar cuz I has a lathe) Standard weighted blowback bolt The total reciprocating mass is in the 28oz range, you need the extended tube for the extra 1.5" of weight added between bolt and buffer. It really does feel like a totally different gun. Zero bolt bounce too. There is a similar thread to this one here: https://www.ar15.com/forums/armory/-/48-542324/? He posted the following over on that thread: Quoted: A straight blowback 9mm, like the Aero EPC, or Scorpion, is probably not a good choice for the wife and kids. Yes, they're cheaper, but the recoil impulse sucks compared to the delayed blowback. Best ways to describe it is "abrupt", "snappy", "punchy", or "sharp". My wife hates my 9mm AR's, but loves the MP5. She's no stranger to recoil, either. I recently embarked on a project specifically to try to knock down the recoil of the straight blowback 9mm AR without using a delay system. You can read about it here if you like: the Gentle Recoil Project. This removed all the snappiness from the recoil for about $200 in parts, and the shooting experience is much better, but in side-by-side comparisons it's still not as good as an MP5. For the family, go with a delayed blowback system - SP5, MPX, or CMMG RDB. Don't waste your time on a straight blowback - and that's coming from someone who loves the straight blowback platform. It'll likely sit in the safe instead of getting used. |
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Quoted: @Droppoint is the guy that did the 'gentle recoil project'. There is a similar thread to this one here: https://www.ar15.com/forums/armory/-/48-542324/? He posted the following over on that thread: Here's the whole writeup: “Gentle Recoil” 9mm AR Project (with testimonials – it really works!) It does the best job of taming recoil in a direct blowback that I've found for less than $200. Most delayed blowbacks will still be superior at mitigating recoil, but are much more expensive. |
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Quoted: As someone who is heavily invested in colt smg mags I cant really go with any of the others without modification of something else. Are you saying you must stick to straight blowback to use your Colt SMG mags? If so, that isn't the case. Since this thread is discussing 'not-blowback' options, you can do a CMMG RDB with your unmodified Colt mags and sounds like you should be able to use the MEAN Arms upper as well. Now, if you have a 'fixed' Colt mag lower, you would still need to modify your feed ramp, remove the fixed ejector, swap your LRBHO and mag catch. I say swap assuming you don't want to mod your existing. CMMG also sells a kit to swap the parts so you don't have to mod anything but I think that is for their straight blowback Colt mag lowers. They have two versions one for Duramags and one for Colt / Metalform. Link to my website on what I did to get unmodified Colt mags to work with my CMMG RDB: https://c3junkie.com/?page_id=374 I presume that the MEAN Arms will work with my lower above.  9mm CMMG Guard and Colt mags |
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Quoted: I don't understand what you mean by that. Are you saying you must stick to straight blowback to use your Colt SMG mags? If so, that isn't the case. Since this thread is discussing 'not-blowback' options, you can do a CMMG RDB with your unmodified Colt mags and sounds like you should be able to use the MEAN Arms upper as well. Now, if you have a 'fixed' Colt mag lower, you would still need to modify your feed ramp, remove the fixed ejector, swap your LRBHO and mag catch. I say swap assuming you don't want to mod your existing. CMMG also sells a kit to swap the parts so you don't have to mod anything but I think that is for their straight blowback Colt mag lowers. They have two versions one for Duramags and one for Colt / Metalform. Link to my website on what I did to get unmodified Colt mags to work with my CMMG RDB: https://c3junkie.com/?page_id=374 I presume that the MEAN Arms will work with my lower above.  https://www.youtube.com/watch?v=cmAdCXDTUgcGuys at MEAN arms said that it would not work with Colt SMG style mags. Thats from the IV8888 shoot a year or so ago. Unless they have made a change. I have also seen your write up 2-3 times on your conversion for the RDB system and dont feel like messing with my feed ramp on my mag block. Id rather have a turn key no fuss conversion. I also haven't shot my 9mm sbr in like a year so not that pressing of issue. lol I just want to make it quieter than what it is when suppressed. |
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Quoted: Id rather have a turn key no fuss conversion. I just want to make it quieter than what it is when suppressed. Delayed blowback is noticeably quieter. |
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Quoted: If your Colt mag lower is a CMMG then it would be turn key with their kit. Or if your lower is compatible with their kit....obviously assuming the MEAN works or if you wanted to go with the CMMG RDB. Delayed blowback is noticeably quieter. For sure night and day difference. They said the mean bolt would only work with Glock or mean mags and their barrel I think. My 9 is an Anderson lower with a bottom load to screw locked magwell adapter. It works great actually never had an issue with it come to think. Just don’t really feel like tinkering with anything else right now. Got so many other half completed jobs to finish first. |
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Quoted: Bearing Delay upper is getting some press. Interested in this one but will wait for barrel and bolt being offered separately. |
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Quoted: For sure night and day difference. They said the mean bolt would only work with Glock or mean mags and their barrel I think. My 9 is an Anderson lower with a bottom load to screw locked magwell adapter. It works great actually never had an issue with it come to think. Just don’t really feel like tinkering with anything else right now. Got so many other half completed jobs to finish first. Quoted: Quoted: If your Colt mag lower is a CMMG then it would be turn key with their kit. Or if your lower is compatible with their kit....obviously assuming the MEAN works or if you wanted to go with the CMMG RDB. Delayed blowback is noticeably quieter. For sure night and day difference. They said the mean bolt would only work with Glock or mean mags and their barrel I think. My 9 is an Anderson lower with a bottom load to screw locked magwell adapter. It works great actually never had an issue with it come to think. Just don’t really feel like tinkering with anything else right now. Got so many other half completed jobs to finish first. If it won't work on a standard AR-15 lower with a magblock for Colt mags that'd be a bummer, but I can see how the feedramp built into the magblock could cause issues. If the Mean upper and bolt end up being the shit I might just switch the wife over to using the Endo mags and remove the magblock altogether from the KP-15 lower. |
| Anyone try this setup from maxim?https://maximdefense.com/product/244978/ |
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Quoted: Anyone try this setup from maxim?https://maximdefense.com/product/244978/ Well dang, almost exactly what i was experimenting with before going with a Kynshot.... Will have to try one out. Attached File |
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Quoted: Anyone try this setup from maxim?https://maximdefense.com/product/244978/ Interesting. So it’s a simple swap out of the buffer and spring for this thing? Does it have a proprietary buffer tube like the other roller system linked earlier in the thread or can it be used with any standard carbine buffer tube? |
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Quoted: Interesting. So it’s a simple swap out of the buffer and spring for this thing? Does it have a proprietary buffer tube like the other roller system linked earlier in the thread or can it be used with any standard carbine buffer tube? Quoted: Interesting. So it’s a simple swap out of the buffer and spring for this thing? Does it have a proprietary buffer tube like the other roller system linked earlier in the thread or can it be used with any standard carbine buffer tube? From the specs: One of the main benefits of the RDB system is its ability to install on Mil-Spec AR-15/AR-9 easily. Our RDB system replaces the buffer and spring of your AR-9, making it simple and easy to install. The system also fits perfectly into the Maxim Defense CQB Length Buffer Tube, ensuring a seamless fit and maximum performance. Seems like a seamless direct swap? |
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Quoted: Anyone try this setup from maxim?https://maximdefense.com/product/244978/ Well that has my attention…. |
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Quoted: Well that has my attention . Quoted: Quoted: Anyone try this setup from maxim?https://maximdefense.com/product/244978/ Well that has my attention . I personally think the cyclic rate will be at least around 900RPM with that with setup. Spring choices will most likely be limited as well probably no buffer options. So someone like me trying to tune the RoF down, isn't ideal for me....but a great option for most people that don't care if it works |
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Quoted: That is pretty slick and hope it works well. Always great to see more options and innovations. I personally think the cyclic rate will be at least around 900RPM with that with setup. Spring choices will most likely be limited as well probably no buffer options. So someone like me trying to tune the RoF down, isn't ideal for me....but a great option for most people that don't care if it works But for semi-auto shooters like most of us, what do you think? I like the principle and the cost is reasonable. But if it won't work 100% what's the point?!? |
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Quoted: Anyone try this setup from maxim?https://maximdefense.com/product/244978/ I ordered one on Friday. No shipping info yet. I'll post it on my site once I complete the testing. If I remember I'll post it on arfcom as well. I also have an adapter on order to hopefully allow it to work with a Law Tactical folder. Blowback9.com |
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Quoted: But for semi-auto shooters like most of us, what do you think? I like the principle and the cost is reasonable. But if it won't work 100% what's the point?!? Quoted: Quoted: That is pretty slick and hope it works well. Always great to see more options and innovations. I personally think the cyclic rate will be at least around 900RPM with that with setup. Spring choices will most likely be limited as well probably no buffer options. So someone like me trying to tune the RoF down, isn't ideal for me....but a great option for most people that don't care if it works But for semi-auto shooters like most of us, what do you think? I like the principle and the cost is reasonable. But if it won't work 100% what's the point?!? I'll hold out for the MEAN unless some can get one of these running full auto in the 600's SMOOTHLY but doubt that is possible. |
| My competition PCC is a CMMG RDB setup, but I also have an MP5 clone and a Scheel roller delayed buffer in another gun. I ordered one of the Maxim recoil assemblies and I will compare it to all of the above, as well as attempt to test it with my CMMG setup to see if it really is too much of a good thing. |
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Quoted: My competition PCC is a CMMG RDB setup, but I also have an MP5 clone and a Scheel roller delayed buffer in another gun. I ordered one of the Maxim recoil assemblies and I will compare it to all of the above, as well as attempt to test it with my CMMG setup to see if it really is too much of a good thing. Sounds like you're set up with all available operating systems for comparison. Looking forward to your findings between the Scheel and Maxim. |
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Quoted: My competition PCC is a CMMG RDB setup, but I also have an MP5 clone and a Scheel roller delayed buffer in another gun. I ordered one of the Maxim recoil assemblies and I will compare it to all of the above, as well as attempt to test it with my CMMG setup to see if it really is too much of a good thing. Look forward to review |
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Quoted: Yeah principle seems legit. Like you said, price is reasonable and they will sell a ton if it works. I'll hold out for the MEAN unless some can get one of these running full auto in the 600's SMOOTHLY but doubt that is possible. Quoted: Quoted: Quoted: That is pretty slick and hope it works well. Always great to see more options and innovations. I personally think the cyclic rate will be at least around 900RPM with that with setup. Spring choices will most likely be limited as well probably no buffer options. So someone like me trying to tune the RoF down, isn't ideal for me....but a great option for most people that don't care if it works But for semi-auto shooters like most of us, what do you think? I like the principle and the cost is reasonable. But if it won't work 100% what's the point?!? I'll hold out for the MEAN unless some can get one of these running full auto in the 600's SMOOTHLY but doubt that is possible. I ordered one too. I'll get some full auto cyclic rate data points for the Maxim RDB setup. I figure might as well get one since the price isn't crazy and the way things go in this industry, they may stop making them and I may wish I had one for some reason and since I don't use my straight blowback Colt 9mm setup anymore, maybe it will give me a reason to use it in semi at least. |
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