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Posted: 8/19/2018 12:28:06 AM EDT
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I don't have a 9mm pcc and I need one. What is the best way to go? I don't want a problem child and only want to buy things once. CMMG guard, FM, Macon ect ect. Does the Radial blowback delay on the CMMG make a big difference? I see FM is coming out with their own system. I have built a few AR's over the years but the PCC's seem like a different animal when it comes to matching parts that work. I want a short barrel 5 to 8", I will run it subsonic suppressed the majority of the time. Thanks |
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I can't speak for the CMMG but if their delayed blowback works anywhere near as well as the HK mp5's roller delayed it will be the one to beat. Straight blowback sucks. Several threads discussing this. Here is one in regards to full auto: https://www.ar15.com/forums/Armory/RLL-and-CMMG-Radial-Delayed-Blowback-System-for-9mm/23-490132/ I've been playing around with blowback Colt 9mm setups since around 2003. Using them for SMG competitions and was always disappointed in how choppy they run. Best I could do was run the LRM suppressed ported barrel setup and an old Olympic Pneumatic buffer which eventually started to leak and was useless. Always wanted an MP5 as it is in my opinion the gold standard when it comes to smoothness in a closed bolt 9mm SMG. Now that the 9mm Guard came out, I've been playing with it and so far I'm pretty happy with it. I got just the 8" barrel and BCG combo and stripped Guard lower. As mentioned, I'm using a Tubbs flat wire 556 spring, A5 tube and Blitzkrieg/Kynshot hydraulic buffer. Very smooth. Very close to a full auto MP5K PDW. Due to the Guard testing, I stumbled on this buffer tube, buffer and spring combination which works with all my 556 uppers and also works great with my 9mm FM9 belt fed upper. All that said, my criteria is primarily for full auto usage and such I am concerned with slowing down the cyclic rate. If you are running just semi only, this is not a concern. The trend these days for blowback configurations is to throw a lot of mass at the bolt/buffer and use a strong spring so that it never bottoms out on the rearward stroke. Going that route would be cheaper than going with the Guard but that would be a dedicated build. I am also really curious to see more details of the new FM Products operating system so I would hold off a bit to see what they have come up with if you haven't built up anything yet. |
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I don't think a semi 9mm AR is worth it.
My thoughts and my thoughts only. I have an M16 and a link, and 2 SBR 9mm lowers. One is dedicated Colt and one is dedicated Glock via the magwell. In semi, those guns are eclipsed by dedicated and modern 9mm rifles. Think B&T, CZ, Sig, or whatever. If you want a 9mm rifle, there are better choices in my opinion. If you want to go full auto with an M16 (receiver, sear, link) then it makes sense. Even then, I almost always choose my heavily Laged Mac, mini Uzi (ROF reduced) or my BRP. I do pick my modded Mac most often, as its just so much fun (and accurate). I do take out the Colt 9mm on full auto with the link, but its just not as reliable as the Mac. It is finicky with ammo and requires more attention to run. Yes, I completely understand that I am using a link in 9mm, so the system wasn't designed for those many variables. But if you want a 9mm AR in auto, there aren't that many choices. If I had an HK sear, there wouldn't even be a discussion. However, I'm not getting a sear. So I'm assuming you are going semi in 9mm, I'd recommend another platform. I know I know its not a popular position. My experience is with 2 SBR 9mm lowers, a RR, a LL, a drop in Colt 9mm magwell, a drop in Glock 9mm magwell, 4 9mm uppers. I wish I would have gone with a CZ or something else. I know I still can go that route, but I've got other (gun) projects looming. Now if you require a 9mm AR for work, training, whatever. It is a good platform, I just don't think its the best for 9mm. |
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I almost always choose my heavily Laged Mac, mini Uzi (ROF reduced) or my BRP. I do pick my modded Mac most often, as its just so much fun (and accurate). I do take out the Colt 9mm on full auto with the link, but its just not as reliable as the Mac. It is finicky with ammo and requires more attention to run. Yes, I completely understand that I am using a link in 9mm, so the system wasn't designed for those many variables. But if you want a 9mm AR in auto, there aren't that many choices. If I had an HK sear, there wouldn't even be a discussion. However, I'm not getting a sear. You should try a 9mm Guard setup. It is so smooth that I no longer feel like I need to drop the coin for an HK sear. I was testing my 9mm Guard side by side a post sample MP5K. I think the MP5 definitely looks cooler w/ it's classic lines and super smooth action but with the 9mm Guard, I get way better ergonomics, just about as smooth, better trigger (Geissele SSF), slower AND configurable RoF, easier to mount optics/accessories, easier to work on and buffer systems are always evolving for the AR platform while the HK platform is what it is....and again on the point of evolving is FM Products working on some kind of delayed blowback mechanism for the 9mm AR platform...I'm hoping they come up with some kind of delayed roller blowback in the carrier and use standard blowback barrels...that would be awesome. I see your point but as an owner of a post sample Sig MPX, I'm still not impressed. I personally think they do not suppress well being piston operated. The MP5 and Guard both suppress way better and do NOT rely on the gas system. Not interested in the CZ being a blowback design. BT APC9 is also blowback w/ a hydraulic buffer...(using a hydraulic with my 9mm Guard now.....mmmmm hydraulic + delayed blowback is NICE) I personally like options and there are just so many options with the AR platform that I don't get bored. Sure there are newer designs but again I find it disappointing that all but one in this discussion isn't straight blowback. I personally don't want to go away from the AR platform unless it has some kind of delayed action that will be super smooth and lightweight. Another plus is that if you stick with the AR platform and not going to drop the coin for full auto, you can more readily get some kind of binary trigger for the AR platform than many of these newer platforms. 
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Thanks for all the replies. I have a number of AR's , registered SBR's and suppressors. I live in a fun hating state so auto's are not on my list. I simply enjoy shooting. I used to compete years ago, to much time and money. I am lucky that I have a range on my property and I enjoy the AR ergos. I just want a nice short barreled 9mm to suppress and ring a little steel with. I have no interest in the MPX but the guard and hopefully the FM project will be good. I haven't purchased any dedicated 9mm built parts. My #1 concern is I don't want a problem child. |
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Why do you not like the MPX? It fits the bill with the ar controls and overall is a good package. Also have you considered a mp5? You don't get the ar controls but if you want something that will just work a zenith, dakota tactical, real hk, etc should all work well. People seem to like the new ptr guns so far although I haven't played with one. A zenith or ptr host starts at like 1600 or 1700 bucks. So more expensive than most 9mm ar style guns but not like dakota tactical or real hk expensive. |
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My #1 concern is I don't want a problem child. If you want trouble free go with a Macon Armory barrel. It is the best feeding of the barrels I own, two of the other three needed feed ramp modifications to work reliably. I would also use Macon's 9mm buffer and pair it with Tubb's flat wire AR-10 recoil spring for smooth and comparatively soft recoil. His bolt has been flawless with the Stern Defense bolt the only other one I would consider. I've never had a failure to feed or any problem with my Macon build and shoot hollow points the majority of the time. I've shot numerous groups right around an inch or under at 50 yards (10 shots) with my reloads Some factory ammo can shoot that tight. So far the most consistently accurate ammo has been Remington Golden Sabre's and Speer Gold Dots. Macon Armory's barrel, bolt and buffer led to a positive first experience so I knew the system could work. This gave me the confidence to work with the other builds until they ran as reliable as the Macon Armory stuff. Otherwise I might have quit, thinking 9mm and AR's didn't go together. Another bonus, Rudy at Macon Armory will go above and beyond to help you get things running right if you experience problems. Hope that helps! |
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I have no doubt that Macon's (Rudy's) system will run well. My friend has a 45 Di setup from him. I have spoke to Rudy many times at Knob Creek and he is a great guy. I was just interested in the lastest systems. That is why I was asking about the Guard and the FM system. Everyone says they have low recoil and are fun to shoot. I wish I knew what the FM system was going to be. |
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@amphibian
That’s high praise for the Guard. Especially coming from someone with your experience. I initially discounted the Guard since it is proprietary. In the sense it’s a proprietary AR build. Clearly I need to revisit the platform. Can you tell me more about your Guard? Is yours dealer only or sear / LL? I’d like to duplicate your set up. |
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@amphibian That's high praise for the Guard. Especially coming from someone with your experience. I initially discounted the Guard since it is proprietary. In the sense it's a proprietary AR build. Clearly I need to revisit the platform. Can you tell me more about your Guard? Is yours dealer only or sear / LL? I'd like to duplicate your set up. I found out later that the upper is clearanced more for the Guard. I knew it was for the 45 but noticed they did the same for the 9mm. I didn't have any malfunctions that I would think would be related to the ejection port not being large enough but ordered an Aero Precision 458 Socom upper just to be safe. I know Anderson makes them also. I'm using a RDIAS with my Guard setup. I had also wanted to try using it with Colt mags. I detailed what it took to get it to work with unmodified Colt mags here: http://c3junkie.com/?page_id=597 Buffer/spring testing is documented here: http://c3junkie.com/?page_id=538 You may note that all that buffer/spring testing was done with the Glock mags. After I had everything running the way I wanted, I tried running the Colt mags and found that since the Colt mags require more force to strip the rounds that my setup wasn't as reliable as with the Glock mags unless I went down in buffer and carrier weight. As seen in my link above, I liked running the A5 buffer tube, 556 Tubb flat spring, 9mm Kynshot/Blitzkrieg buffer and used the standard 9mm Colt weight in the carrier. However, when switching to running the steel Colt mags, I had to remove the 9mm Colt weight and go to a lighter weight buffer which then also required me to add an insert as seen on the right side of the buffer spring in the picture below to prevent the buffer from bottoming out since I was still running the A5 length tube. I think you need more BCG velocity when relying on the ejector in the bolt. 
All that said, I think I've mentioned that tinkering with the Guard system, I stumbled on this buffer/spring configuration that I'm now using on almost all of my other upper configurations. It has greatly smoothed out my go to setup which is a 12.5" suppressed Mid Gas system w/ a Brevis II Ultra. It also worked wonders on the belt fed Shrike. The Shrike is normally very fast and kinda violent. I can now easily pull singles with the Shrike in auto. I also have the belt fed 9mm FM9 which is blow back and it has smoothed that out also. For some reason, this buffer has issues with my 7.62x39 configurations though. Getting light hits on those. I still need to use a heavy mechanical buffer on those. Here is also some more info on the 'A5' tube setup here: http://c3junkie.com/?page_id=571 Pictured below is standard carbine tube, then PSA PA10 tube and then a Vltor A5 tube....if you don't want to drop the coin on A5 you can get the PSA PA10 for $20 and it has the same depth. 
I also did the pre-order of the MEAN Arms Endo mag: https://www.ar15.com/forums/ar-15/Anyone-seen-this-MEAN-Arms-9mm-adpater-/15-728601/&page=4 I'm hoping that the rounds are stripped just as easily with the Endo mag as it is with Glock mags, if so, I will probably switch over to using those instead of Glock mags. |
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As far the the lower goes. You bought a standard 556 CMMG Guard lower? Then added your internals? Edit. As opposed to the CMMG Guard 9mm lower that is a Glock magazine variant. Then after tuning, went to my MGI Modular lower and used a 556 Mag well with a 9mm Hahn block that is bolted in position as seen below. However, as mentioned went back to the Glock mags due to more force being required to strip rounds from the metal 9mm Colt mags. 
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Ok. Now I'm following you.
Did you use the MGI for other reasons (like good trigger, etc) or was there a specific 9mm Guard reason to use the MGI? If I get the CMMG Guard 9mm barrel and carrier combo, will that work on an in spec lower? I'm asking because I already have the lowers SBR'ed, milled out to accept my link and have the modified burst trigger installed. It would be very easy for me to just swap out the uppers. Also, CMMG states that kit (link) is only guaranteed to work on a CMMG lower and a modified upper. Is that why you bought a 458 upper for more clearance (i.e. modified)? I'd probably buy the full Guard upper. The barrel / bolt is 375 and the full upper is $700. Modified or not modified upper, that'll be out of the equation. I think Id have to get the carrier worked on, but that would be easier than getting another lower and doing all that to it. Meaning, for the link to properly work, I may need to modify the CMMG carrier. I had to make minor modifications my link compatible carriers. Like I said, it was minor. I too am waiting and anticipating the Mean Arms 9mm PMAG inserts. I have preordered 6. If they work well, my dedicated Colt and Glock lowers will be obsolete. I have all the springs and buffers to mix and match as needed. Am I on the right track now? |
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Ok. Now I'm following you. Did you use the MGI for other reasons (like good trigger, etc) or was there a specific 9mm Guard reason to use the MGI? If I get the CMMG Guard 9mm barrel and carrier combo, will that work on an in spec lower? I'm asking because I already have the lowers SBR'ed, milled out to accept my link and have the modified burst trigger installed. It would be very easy for me to just swap out the uppers. Also, CMMG states that kit (link) is only guaranteed to work on a CMMG lower and a modified upper. Is that why you bought a 458 upper for more clearance (i.e. modified)? I'd probably buy the full Guard upper. The barrel / bolt is 375 and the full upper is $700. Modified or not modified upper, that'll be out of the equation. I think Id have to get the carrier worked on, but that would be easier than getting another lower and doing all that to it. Meaning, for the link to properly work, I may need to modify the CMMG carrier. I had to make minor modifications my link compatible carriers. Like I said, it was minor. I too am waiting and anticipating the Mean Arms 9mm PMAG inserts. I have preordered 6. If they work well, my dedicated Colt and Glock lowers will be obsolete. I have all the springs and buffers to mix and match as needed. Am I on the right track now? I didn't want to get the Glock fed Guard lower but I wanted to get the basic components of a 'factory' Guard configuration as a baseline for how it should run rather than start off with my 'FrankenGuard' configuration and then wonder if the system is viable if I have issues. I am glad I did go the route I did as I learned that the same buffer/spring/buffer tube configuration that would work on the factory Guard Glock lower wouldn't run as reliable with the Colt mags just due to the friction involved in stripping the rounds off the Colt mags. I have plenty of rails and charging handles laying around so it made sense for me to just get the barrel/BCG and 458 upper. Anderson sells their 458 Socom upper for $57 and Aero is $79. So for $432 or $455 you would be covered. Of course as a RLL owner, you will need to get the carrier milled out to SP1 specs. I also have 6 Endomags pre-ordered. I've requested half of them to have the ejectors removed for the Guard while the others will have the ejectors left untouched. I figure that if they don't run as smooth as the Glock mags that I may not use them for the Guard. If they do run as smooth then I may just cut the ejectors off the other 3. Another option is I'm waiting to see what the new FM Products delayed blowback looks like. I'm guessing they would still rely on the ejector in the lower or who knows maybe a fixed ejector in the upper. |
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This thread has been very helpful to me. Thank you. I'm thinking of the "Banshee" upper just to save 3 inches of barrel length. I have several 9mm uppers. 3 inch 5 inch x 2 10 inch. I almost always shoot the 3 and 5s. I don't bother with a suppressor on the 10. |
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Sounds great. A Brevis is on my list to buy as well. I finally got Silencer Shop stuff ironed out. I’m getting a Bowers 458 transferred, that’s progressing. Next is a Brevis. I don’t think you can make the jump, if I go less than 8 inches I’ll just shoot a pistol. Shouldering a rifle even with a 5 inch barrel will still be more accurate than a 5 inch pistol. In most people’s hands, definately in mine. |
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I don't think you can make the jump, if I go less than 8 inches I'll just shoot a pistol. Shouldering a rifle even with a 5 inch barrel will still be more accurate than a 5 inch pistol. In most people's hands, definately in mine.Of 1. More knockdown power especially for hitting steel plates 2. The same feel and maneuverability as my 'goto' setup. As you can see below, the 9mm Guard upper is about the same length as my 556 setup. I use a 12.5" mid gas on my 556 because it has a smoother recoil impulse than carbine gas and I think the 12.5 has better ballistics than going to a 10.3 or 10.5" Here in FL, my 9mm 8" is subsonic with most 147 and I reload so no biggie there. I am used to shooting my 12.5 mid in and around barricades and such. When I shoot a really short 9mm M16 setup and switch back to 556, I notice I start slamming into stuff since I get used to the shorter configuration. I don't have that issue when I keep them the same length. Now my mind switches if I'm shooting an UZI or some other platform as the manual of arms is all different. When I transition to the 9mm upper, my hand already wants to land beyond the rail of my 9mm Guard....going even shorter would be even worse. I have been thinking about going to a longer rail on the Guard and tuck the can inside so that I can use the same hand placement as my 556...but I really like the old school SCRC (Tim Bixler) 3 lug mount. For those of you that don't know, that is the original 3 lug mount. Absolutely no play in that mount. Rock solid. No springs. But it requires access to the rear of suppressor. I may change it up later after some more testing. 
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I don't have a 9mm pcc and I need one. What is the best way to go? I don't want a problem child and only want to buy things once. CMMG guard, FM, Macon ect ect. Does the Radial blowback delay on the CMMG make a big difference? I see FM is coming out with their own system. |
| As I've already got a couple blow back 9mm uppers, an Uzi mag magwell adapter, and a Glock mag magwell adapter, I'm holding out till some intrepid entrepreneur starts selling a roller delay, blow back (à la the H & K MP5) 9mm AR upper that will accommodate either or preferably both of the adapters. Side charging would be a big plus. |
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Do you (or anyone else) have any more info on the FM system? Quoted:
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I don't have a 9mm pcc and I need one. What is the best way to go? I don't want a problem child and only want to buy things once. CMMG guard, FM, Macon ect ect. Does the Radial blowback delay on the CMMG make a big difference? I see FM is coming out with their own system.  Failed To Load Title I have one. Mine is built on their billet Lower with a 16 inch upper. It’s a blowback 9mm that uses Glock magazines. It’s a side charger, with the charging handle in the handguard. The bolt hold open works perfectly. Mine is accurate and has functioned 100% with all but one load, IMI “die cut” hollow points. These have a jagged HP cavity that hangs up on the feed ramp about 30% of the time. FMP also has great customer service. Very responsive to all my questions, and have sent me some parts (buffer and spring) free. |
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 https://www.youtube.com/watch?v=aHXLAUT-bMc
I have one. Mine is built on their billet Lower with a 16 inch upper. It's a blowback 9mm Quoted:
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I don't have a 9mm pcc and I need one. What is the best way to go? I don't want a problem child and only want to buy things once. CMMG guard, FM, Macon ect ect. Does the Radial blowback delay on the CMMG make a big difference? I see FM is coming out with their own system. https://www.youtube.com/watch?v=aHXLAUT-bMc
I have one. Mine is built on their billet Lower with a 16 inch upper. It's a blowback 9mm This link states, "New operating system is crushing it, almost no recoil. Great products coming online soon! Less mass, less weight, less recoil, no more blow back...coming soon!" https://www.facebook.com/foxtrotmikeproducts/videos/1815497421845455/ That is what we are waiting for...NO MORE BLOW BACK... So what is it? They mentioned 2-3 months back on May 9th. and "we will offer parts to upgrade the existing product lines, it will be more expensive than what we offer now sadly." I'm hoping it will use existing blowback barrels but something different in the bolt/carrier and upper at least... |
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No...we are all referring to their new operating system mentioned on their first post on this page: https://www.ar15.com/forums/AR-15/Foxtrot-Mike-s-9mm-upper-anyone-heard-of-them-/15-715196/?page=7 This link states, "New operating system is crushing it, almost no recoil. Great products coming online soon! Less mass, less weight, less recoil, no more blow back...coming soon!" https://www.facebook.com/foxtrotmikeproducts/videos/1815497421845455/ That is what we are waiting for...NO MORE BLOW BACK... So what is it? They mentioned 2-3 months back on May 9th. and "we will offer parts to upgrade the existing product lines, it will be more expensive than what we offer now sadly." I'm hoping it will use existing blowback barrels but something different in the bolt/carrier and upper at least... Quoted:
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I don't have a 9mm pcc and I need one. What is the best way to go? I don't want a problem child and only want to buy things once. CMMG guard, FM, Macon ect ect. Does the Radial blowback delay on the CMMG make a big difference? I see FM is coming out with their own system. https://www.youtube.com/watch?v=aHXLAUT-bMc
I have one. Mine is built on their billet Lower with a 16 inch upper. It's a blowback 9mm This link states, "New operating system is crushing it, almost no recoil. Great products coming online soon! Less mass, less weight, less recoil, no more blow back...coming soon!" https://www.facebook.com/foxtrotmikeproducts/videos/1815497421845455/ That is what we are waiting for...NO MORE BLOW BACK... So what is it? They mentioned 2-3 months back on May 9th. and "we will offer parts to upgrade the existing product lines, it will be more expensive than what we offer now sadly." I'm hoping it will use existing blowback barrels but something different in the bolt/carrier and upper at least... |
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Perhaps the new FM upper implements a gas-operated, short stroke piston, rotating bolt system similar to the system used in the H & K MP7. |
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I don't have a 9mm pcc and I need one. What is the best way to go? I don't want a problem child and only want to buy things once. CMMG guard, FM, Macon ect ect. Does the Radial blowback delay on the CMMG make a big difference? I see FM is coming out with their own system. I have built a few AR's over the years but the PCC's seem like a different animal when it comes to matching parts that work. I want a short barrel 5 to 8", I will run it subsonic suppressed the majority of the time. Thanks subsonics, and the manufacturer of the PTR 9CT (i.e. PTR) does not guarantee it will properly feed HP ammo. |
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Note: a barrel length over about 5.5 inches is not optimal for subsonics. To me, optimal would be the highest velocity while still remaining subsonic. I want maximum knock down power but still subsonic. Bear in mind that the speed of sound varies depending on the density of the air, temperature, altitude etc. I'm in FL and even at 9" (3lugged UZI barrel) I'm still subsonic with 147 Gr unless we are talking about self defense 147Gr loads. Below is chrony data for my ~9" full size UZI SMG. Full Size Open Bolt UZI, 3 lugged IMI barrel Unsuppressed147 Gr Precision Delta COL 1.169 Titegroup 3.7 Gr (max charge is 3.6 Gr) 943.8 911 967.7 941.4 920.3 936.84 AVG. I know competitors also shooting full size UZI's that have increased their powder charge to 4.0 Gr of Titegroup since again we want to be subsonic but max power so I tried it myself with the following data: Full Size Open Bolt UZI, 3 lugged IMI barrel Unsuppressed 147 Gr Precision Delta COL 1.169 Titegroup 4.0 Gr (again max charge is 3.6) 1032.1 1145.9 1202.8 1103.7 1051.1 1107.12AVG Right on the edge of the speed of sound with a few spilling into supersonic. I did both of those tests years back in the summer. In the winter time, the 4.0Gr load is consistently supersonic in FL, so I've been using my 3.7Gr load for over a decade now as I know it works year round. I know that it is subsonic in my 9" UZI and so it is also subsonic in the Mini UZI as well as the 8" CMMG Guard and all handguns I have. Note that while both of the loads above are subsonic, the slower one is slightly quieter when suppressed since the suppressor has less pressure to deal with. So again, this comes back down to personal preference in what you regard as 'optimal'. If sound reduction is more important than knock down power then I would test function at the Hodgdon manual starting load of 3.2 Gr. |
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Very good thread.
Couple of questions. 1. Why a 458 upper for a banshee/guard build and not a 556 upper? Is the opening on a 556 upper too thin becsuse obviously the length should be enough. 2. To Amphibian using the A5 tube, why not just run an A5 buffer? I’m trying to figure out what weight I would need in an A5 buffer with an 8” Guard. 3. The Mean PMAG adapters that make the 556 mags into 9mm... those look awesome but am I wrong that they move the feed lips to each mag? That if you had 6 mags and the feed angle wasn’t entirely right you would need to modify 6 mags right? I wonder if the mfg has different ramp options for different uppers? 4. Does anyone know if a guard barrel on a 556 upper needs a special 9mm trigger / hammer or would an SAA/SSA-E work? I wasn’t at all infested in a 9mm AR platform until I realized I could clone my 556 gun almost entirely into something I could shoot USPSA with. I could use that game as 556 training. |
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Very good thread. Couple of questions. 1. Why a 458 upper for a banshee/guard build and not a 556 upper? Is the opening on a 556 upper too thin becsuse obviously the length should be enough. 2. To Amphibian using the A5 tube, why not just run an A5 buffer? I’m trying to figure out what weight I would need in an A5 buffer with an 8” Guard. 3. The Mean PMAG adapters that make the 556 mags into 9mm... those look awesome but am I wrong that they move the feed lips to each mag? That if you had 6 mags and the feed angle wasn’t entirely right you would need to modify 6 mags right? I wonder if the mfg has different ramp options for different uppers? 4. Does anyone know if a guard barrel on a 556 upper needs a special 9mm trigger / hammer or would an SAA/SSA-E work? I wasn’t at all infested in a 9mm AR platform until I realized I could clone my 556 gun almost entirely into something I could shoot USPSA with. I could use that game as 556 training. And the OP's original discussion was about 9mm PCC. The thread went completely off-topic, and was pretty much over. What you did is refereed to as "thread hijacking" where you go into someone else's thread and ask for your own questions to be answered. Some questions you are asking, Like the maen arms adapter and what trigger works, already have threads that are current, and you should be reading or asking in those threads. Others can be answered with a quick search. _ |
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Oh, yea, MY BAD, smfc. Except that FM doing a delayed blowback and technical questions on the CMMG would be entirely on topic. Threads change. OP might be long gone, but as the topic moved to excellent CMMG details, I don't mind continuing the new topic. I found this CMMG data heavy post by searching, someone else in the future will as well. |
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1. Why a 458 upper for a banshee/guard build and not a 556 upper? Is the opening on a 556 upper too thin becsuse obviously the length should be enough. Not a matter of being too thin...the 458 upper's ejection port is larger...the Guard and other PCC's that use the ejector in the bolt have a different ejection pattern....so a larger port is definitely needed for those 45ACP setups...not sure about 9mm but the Guard ships that way so I just did the same thing. 2. To Amphibian using the A5 tube, why not just run an A5 buffer? I'm trying to figure out what weight I would need in an A5 buffer with an 8" Guard. I did try various buffers as well as the A5 buffers...http://c3junkie.com/?page_id=538 H3 buffer is 5.3 oz and an A5H2 buffer (standard A5 weight) is also 5.3 oz. I couldn't get more than 7 rounds off in full auto with that weight. Eventhough the 9mm Kynshot/Blitzkrieg is 5.9 oz, I didn't have malfunctions like I did with the A5H2 or H3 w/ spacer in the A5 tube. Not sure why. I guess something to do with the sliding weights and timing? 4. Does anyone know if a guard barrel on a 556 upper needs a special 9mm trigger / hammer or would an SAA/SSA-E work? I'm using a Geissele SSF (RDIAS, Full auto) with my Guard and have also used factory Colt full auto fire control...don't see why there would be any issues with the SAA/SAA-E |
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I don't have a 9mm pcc and I need one. What is the best way to go? I don't want a problem child and only want to buy things once. CMMG guard, FM, Macon ect ect. Does the Radial blowback delay on the CMMG make a big difference? I see FM is coming out with their own system. I have built a few AR's over the years but the PCC's seem like a different animal when it comes to matching parts that work. I want a short barrel 5 to 8", I will run it subsonic suppressed the majority of the time. Thanks |
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