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Posted: 10/4/2019 10:31:01 PM EDT
[#1]
Quote HistoryQuoted:
Just out of curiosity, has anyone installed the 9mm shell deflector and dust cover on a guard? I've got one of the cmmg ones in my parts bin. I installed one initially purely for that nostalgic Colt SMG 'look' but had issues exactly as CMMG described - empty brass would bounce back into the action causing stovepipe-style malfunctions. |
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Posted: 10/4/2019 11:23:30 PM EDT
[#2]
Quote HistoryQuoted:
I have an SBR QC10 small frame Glock lower. I removed the extractor and feed ramp from the lower and am able to put the 9mm banshee upper and lower together. Unfortunately I'm unable seat empty Glock mags on a closed bolt. Is this normal for this upper/lower combo? Am I going to have modify the bolt catch to make the mags seat lower? How a link on how I did it in the archives. https://www.ar15.com/forums/ar-15/CMMG-RDB-System-on-DDLES-Glock-Lower-With-NFA-LRBHO-Upper/15-742058/ A major difference is that I run a New Frontier Armory LRBHO upper with a CMMG RDB bolt and barrel on my SBR. I did test my modified lower with a factory CMMG RDB complete upper and it works fine although this particular setup no longer locks back on an empty mag. I had to remove the DDLES LRBHO from my lower since it interfered with the LRBHO in the NFA upper. My link might give another idea on how to get your CMMG upper to run on your QC10 lower but I don’t really know if your LRBHO will work with your combination. |
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Posted: 10/5/2019 10:37:00 AM EDT
[#3]
Quote HistoryQuoted:
I have a DDLES SBR’d lower. It’s essentially the same as the current QC10 lowers. I found that I had to modify the mag release and limit how far the mag would seat in the lower due to interference problems between the bolt and mags. I didn’t do any mods to my mags since I also use them in my Glock 17 but I did do a little work on the bottom lugs of the CMMG bolt to reduce gouging on the rounds in the mag. How a link on how I did it in the archives. https://www.ar15.com/forums/ar-15/CMMG-RDB-System-on-DDLES-Glock-Lower-With-NFA-LRBHO-Upper/15-742058/ A major difference is that I run a New Frontier Armory LRBHO upper with a CMMG RDB bolt and barrel on my SBR. I did test my modified lower with a factory CMMG RDB complete upper and it works fine although this particular setup no longer locks back on an empty mag. I had to remove the DDLES LRBHO from my lower since it interfered with the LRBHO in the NFA upper. My link might give another idea on how to get your CMMG upper to run on your QC10 lower but I don’t really know if your LRBHO will work with your combination. Quote HistoryQuoted:
Quoted:
I have an SBR QC10 small frame Glock lower. I removed the extractor and feed ramp from the lower and am able to put the 9mm banshee upper and lower together. Unfortunately I'm unable seat empty Glock mags on a closed bolt. Is this normal for this upper/lower combo? Am I going to have modify the bolt catch to make the mags seat lower? How a link on how I did it in the archives. https://www.ar15.com/forums/ar-15/CMMG-RDB-System-on-DDLES-Glock-Lower-With-NFA-LRBHO-Upper/15-742058/ A major difference is that I run a New Frontier Armory LRBHO upper with a CMMG RDB bolt and barrel on my SBR. I did test my modified lower with a factory CMMG RDB complete upper and it works fine although this particular setup no longer locks back on an empty mag. I had to remove the DDLES LRBHO from my lower since it interfered with the LRBHO in the NFA upper. My link might give another idea on how to get your CMMG upper to run on your QC10 lower but I don’t really know if your LRBHO will work with your combination. @azdover |
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Posted: 10/5/2019 5:02:34 PM EDT
[#4]
An update on my issue...
I spoke to cmmg about my issues and they sent me some ejector springs and their carrier tuning kit. So before I start messing around with this on my colt RR; would a standard carbine buffer work safely with adding weight to the cmmg carrier? I just don’t want to risk damaging the lower. The person I spoke with at cmmg recommended going the opposite way I’ve went; decrease buffer weight, increase carrier weight. Currently I’m using the colt x buffer which is a standard length carbine buffer that weights about 8 oz. |
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Posted: 10/10/2019 8:03:21 AM EDT
[#5]
Quote HistoryQuoted: What amphibian said ^ I installed one initially purely for that nostalgic Colt SMG 'look' but had issues exactly as CMMG described - empty brass would bounce back into the action causing stovepipe-style malfunctions. In pics different uppers for CMMG Guard ( and size of deflectors) 
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Posted: 10/11/2019 6:36:12 AM EDT
[#6]
Quote HistoryQuoted:
An update on my issue... I spoke to cmmg about my issues and they sent me some ejector springs and their carrier tuning kit. So before I start messing around with this on my colt RR; would a standard carbine buffer work safely with adding weight to the cmmg carrier? I just don't want to risk damaging the lower. The person I spoke with at cmmg recommended going the opposite way I've went; decrease buffer weight, increase carrier weight. Currently I'm using the colt x buffer which is a standard length carbine buffer that weights about 8 oz. Do you use that Colt X buffer on your 5.56 uppers? I use the same buffer on my CMMG RDB as I do for my 5.56 uppers. All this discussed here: http://c3junkie.com/?page_id=538 Kynshot RB5007, A5 tube, Tubb 556 spring (or Tubb 300BLK if you want to drop the cyclic rate another 30 RPM) 
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Posted: 10/11/2019 4:38:42 PM EDT
[#7]
great info, thanks amphibian!
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Posted: 10/15/2019 7:49:43 AM EDT
[#8]
Hey guys, new to 9mm ARs and about to order a Guard setup to play with on a spare SBR lower. Can anyone tell me if this parts list looks OK/should run smoothly?
- Milspec AR lower - A5 buffer tube, Springco Green spring, A5H3 buffer (may eventually move to amphibian's recommended setup with Kynshot buffer and Tubbs spring) - Geissele S3G trigger - Aero No Forward Assist AR15 upper - CMMG Guard 9mm bolt/ 8" barrel combo - CMMG ARC mags No plans for F/A at the moment, though that could change in the future. Would be 100% suppressed with an AAC TiRant 9M on a 3 lug mount tucked under an ALG handguard. @amphibian - I've read all your stuff and it's been very helpful in settling on this set up |
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Posted: 10/15/2019 9:30:04 AM EDT
[#9]
Quote HistoryQuoted:
Hey guys, new to 9mm ARs and about to order a Guard setup to play with on a spare SBR lower. Can anyone tell me if this parts list looks OK/should run smoothly? - Milspec AR lower - A5 buffer tube, Springco Green spring, A5H3 buffer (may eventually move to amphibian's recommended setup with Kynshot buffer and Tubbs spring) - Geissele S3G trigger - Aero No Forward Assist AR15 upper - CMMG Guard 9mm bolt/ 8" barrel combo - CMMG ARC mags No plans for F/A at the moment, though that could change in the future. Would be 100% suppressed with an AAC TiRant 9M on a 3 lug mount tucked under an ALG handguard. @amphibian - I've read all your stuff and it's been very helpful in settling on this set up A lot of people also say an enlarged ejection port upper is not needed but I just got the Aero XL's to be on the safe side. |
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Posted: 10/15/2019 10:21:30 AM EDT
[#10]
Quote HistoryQuoted:
All that is fine but just in case you don't know the Guard has usable forward assist notches....I know a lot of people hate the FA so if you are one of those people that makes sense. A lot of people also say an enlarged ejection port upper is not needed but I just got the Aero XL's to be on the safe side. |
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Posted: 10/15/2019 10:35:28 AM EDT
[#11]
Quote HistoryQuoted: I'm one of those people and would love to ditch the FA on my Guard. Do you know of any non-foward assist, enlarged ejection port uppers? |
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Posted: 10/15/2019 12:00:06 PM EDT
[#12]
Quote HistoryQuoted: I'm one of those people and would love to ditch the FA on my Guard. Do you know of any non-foward assist, enlarged ejection port uppers? |
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Posted: 10/15/2019 12:09:27 PM EDT
[#13]
@amphibian Thanks! I’m not an FA hater, just didn’t realize the Guard could use a FA. I’ll grab an Aero XL instead
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Posted: 10/22/2019 10:34:57 AM EDT
[#14]
Will these components work in the SBA3 brace. Kynshot RB5007, Tubb 556 spring
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Posted: 10/22/2019 11:23:03 AM EDT
[#15]
The spring would be fine but that Kynshot will be too long for normal cycling in a gun with a carbine length buffer tube like the SBA3. It will bottom out on the back of the tube.
If you're limited to using a carbine length tube, try one of the Kynshot carbine buffers. I think @amphibian tested a few different ones with varying results. |
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Posted: 10/22/2019 11:56:31 AM EDT
[#16]
Quote HistoryQuoted:
The spring would be fine but that Kynshot will be too long for normal cycling in a gun with a carbine length buffer tube like the SBA3. It will bottom out on the back of the tube. If you're limited to using a carbine length tube, try one of the Kynshot carbine buffers. I think @amphibian tested a few different ones with varying results. I would just use an A5 length tube with SBA3. If you must use a carbine length tube, I'd recommend the RB5005. I have all this documented here: http://c3junkie.com/?page_id=430#hydraulic |
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Posted: 10/22/2019 7:43:30 PM EDT
[#17]
thx
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Posted: 10/22/2019 7:46:43 PM EDT
[#18]
Get a PA-10 buffer tube from PSA. Works great with the Vltor A5 system or with a pistol build as you are describing. My parts list is a page or two back. I'm not completely finished but ran it the other day and it works just fine.
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Posted: 10/23/2019 4:59:45 PM EDT
[#19]
I didn't read all 22 pages, so bare with me please
I Have an NFA glock mag lower and the CMMG RDB 9mm barrel and bolt in a standard aero precision upper. Been shooting it successfully with a standard lower and endo mags. Was able to pick up the NFA glock lower and wanted to try it out, as I have many guns that take glock mags and wanted to see how much it would take to work. I removed the ejector and it seemed to work fine. Had it at the range today and it functioned except a couple hang ups in the last round. Feeding issue. Reading the link to the post above makes me think the mag is sitting a hair high. Anyone here do this with a NFA glock lower or is everyone doing rhe DDLS lowers. I think I had 2 ftfs in about 70 rounds. Pic of the jammed round.  Attached File |
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Posted: 10/24/2019 3:22:42 AM EDT
[#20]
Anyone know of a online dealer with the 5" 9mm RDB barrel kit (99D17C3) in stock. I have been looking online for the last two months and everyone seems to still be sold out. Is CMMG still selling the 5" kit?
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Posted: 10/24/2019 3:40:06 AM EDT
[#21]
Quote HistoryQuoted:
Anyone know of a online dealer with the 5" 9mm RDB barrel kit (99D17C3) in stock. I have been looking online for the last two months and everyone seems to still be sold out. Is CMMG still selling the 5" kit? https://gun.deals/search/apachesolr_search/99D17C3 |
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Posted: 10/24/2019 12:22:30 PM EDT
[#22]
Quote HistoryQuoted:
Anyone know of a online dealer with the 5" 9mm RDB barrel kit (99D17C3) in stock. I have been looking online for the last two months and everyone seems to still be sold out. Is CMMG still selling the 5" kit? In stock as i type this |
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Posted: 10/24/2019 2:48:01 PM EDT
[#23]
Quote HistoryQuoted: https://www.primaryarms.com/cmmg-radial-delayed-9mm-barrel-and-bcg-assembly-5 In stock as i type this looks in stock at cmmg's site as well; 349 for 5" kit. Their website is kind of broken. If you select barrels, and 9mm, they are nowhere to be found. You have to scroll thru all the barrels to find it, ctrl-f helps. |
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Posted: 10/25/2019 12:39:45 AM EDT
[#24]
Quoted: When I was looking for an 8" kit I setup a search on gun.deals. Took a couple months for them to show up in stock in a few places and they were gone quick. I don't see any in stock at the link below. You might also contact CMMG and see if they are currently in production or if they are scheduled to be in production in the near future. https://gun.deals/search/apachesolr_search/99D17C3 Quoted: https://www.primaryarms.com/cmmg-radial-delayed-9mm-barrel-and-bcg-assembly-5 In stock as i type this Quoted: https://www.cmmginc.com/product/56086barrel-and-bcg-kit-5-4140cm-sbn-9mm/ looks in stock at cmmg's site as well; 349 for 5" kit. Their website is kind of broken. If you select barrels, and 9mm, they are nowhere to be found. You have to scroll thru all the barrels to find it, ctrl-f helps. |
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Posted: 11/9/2019 8:58:36 PM EDT
[#25]
Getting on the RaDBB bandwagon. I'll be using a CMT UHP9 Glock lower.
Currently running Faxon bolt 8.6oz PCC buffer AR10 carbine spring in carbine tube, 5.5" Roscoe barrel always suppressed. I anticipate having to shave down the top edge of the mag catch to drop the mag, and somehow making an over insertion stop where the ejector sits. Any ideas on that over insertion stop? I'd do the endomags, but I already have TONS of Glock mags. I'd also do the banshee lower, but damn dude $349 for a lower receiver? Last resort I suppose. I'll update here if it works. |
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Posted: 11/12/2019 12:51:15 PM EDT
[#26]
I’ve been having an issue with extraction.
Using the guard upper and the endomags. I think I’ve narrowed it down to my bolt catching on the endomag feedlips. The bolt is hitting them, then slowing down enough to not fully grab onto the empty case to extract it from the chamber. I’m getting some decent wear on the two feedlips(I’m assuming that’s what to call them) they’re the two rails at the front of the insert, in front of the 9mm follower. Anyone else see this issue? Any known fix? It almost seems that the endomag insert is sitting to proud of the pmag. |
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Posted: 11/12/2019 3:04:58 PM EDT
[#27]
Having ejection issues as well! CMMG sent me new ejector springs and still having issues.
My set is with the 8" barrel kit, using cmmg mags, new frontier C4 upper (larger ejection port), carbine buffer and spring. |
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Posted: 11/12/2019 4:20:30 PM EDT
[#28]
Quote HistoryQuoted:
I’ve been having an issue with extraction. Using the guard upper and the endomags. I think I’ve narrowed it down to my bolt catching on the endomag feedlips. The bolt is hitting them, then slowing down enough to not fully grab onto the empty case to extract it from the chamber. I’m getting some decent wear on the two feedlips(I’m assuming that’s what to call them) they’re the two rails at the front of the insert, in front of the 9mm follower. Anyone else see this issue? Any known fix? It almost seems that the endomag insert is sitting to proud of the pmag. |
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Posted: 11/12/2019 6:34:17 PM EDT
[#29]
I bought the bolt and barrel kit. As a project I made an 9mm adapter that uses both Sten and Uzi mags. I didn't have any problems at all except the lack of LRBHO. I did an SMF Tactical Colt style lower and I had nothing but trouble with it. The infamous failure to eject. It did this with Colt style ASC mags most the converted Uzi mags worked fine. It turns out that the ASC magazines were sitting to high and the bolt was rubbing on the feed lips. So I filed the magazine notch so they sit lower and they work great now. I might get the new ejector spring from CMMG just in case.
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Posted: 11/14/2019 9:32:09 PM EDT
[#30]
Quote HistoryQuoted:
Anyone know of a online dealer with the 5" 9mm RDB barrel kit (99D17C3) in stock. I have been looking online for the last two months and everyone seems to still be sold out. Is CMMG still selling the 5" kit? https://www.ar15.com/forums/AR-15/Good-deal-on-9mm-Guard-RDB-bolt-and-barrel/15-745625/ |
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Posted: 11/15/2019 10:39:42 PM EDT
[#31]
Quote HistoryQuoted:
Looks like some distributor has them in stock. Under $300 in this thread. https://www.ar15.com/forums/AR-15/Good-deal-on-9mm-Guard-RDB-bolt-and-barrel/15-745625/ Quote HistoryQuoted:
Quoted:
Anyone know of a online dealer with the 5" 9mm RDB barrel kit (99D17C3) in stock. I have been looking online for the last two months and everyone seems to still be sold out. Is CMMG still selling the 5" kit? https://www.ar15.com/forums/AR-15/Good-deal-on-9mm-Guard-RDB-bolt-and-barrel/15-745625/ |
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Posted: 11/16/2019 7:15:48 PM EDT
[#32]
More to update on and I’m really starting to dislike this whole setup.
Just added the vltor a5 receiver extension, with the tubb spring and the kynshot hydraulic buffer. I have replaced both the ejector and extractor springs in the cmmg bolt. I have done the mean arms “break in” as recommend above as well(which I thought might have solved the issue). But NOPE. Still getting a failure to extract from the chamber(and yes the chamber is clean). This is beginning to get pretty damn discouraging, especially since it seems like I pretty alone with this issue. |
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Posted: 11/16/2019 8:37:47 PM EDT
[#33]
Can you extract a live round from the chamber?
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Posted: 11/17/2019 7:31:31 PM EDT
[#34]
So has CMMG ironed out the issues with the extractor/ejector? I am in the market for another PCC and want to buy the 9mm banshee. It seems several people are having issues around the 1k round count mark.
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Posted: 11/17/2019 8:53:49 PM EDT
[#35]
part 1/2
It's finally complete! My own "Amphibian" 9mm CMMG RDB Build. 
Parts: 5" Bolt + CMMG 9mm Radial delay bolt Aero XL Upper CMMG Gas deflector +port cover Radian Charging handle Seekins Precision MCSR V2 7" (ncie handgaurd but irritating installation with two piece barrel nut timing) ILWT Tri-Lug ILWT Slim Tri-lug flash can/ Rugged Obsidian 45 (still in jail, damn you ATF) Holosun 510c that I stole off another rifle. CMMG MKGs 9mm Gaurd lower Sionics enhanced LPK w/ trigger VLTOR A5 buffer tube Kynshot RB 5007 Tubbs .223 flatwire Spring PWS Castle nut + endplate (these are awesome) OEM 33rd Glock magazines (4 different magazines were tested) First time at the range was the most fun I've had shooting since I got into firearms a couple of years ago. I fed it 50 rds Tulammo, 125 rds of mixed 115gr (magtech, aguila, S&B), 75 rounds each of AE 147 gr and Speer lawman 147gr, and 50 rounds of federal HST 147gr without a single failure, bolt held open for last round each time. New account character limit, second post coming soon. |
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Posted: 11/17/2019 8:57:17 PM EDT
[#36]
I got all the way to approx 1,300 logged rounds without a malfunction across 10 different matches. Last match, match #10, I got a failure to eject. It was easy to clear since it didn't get hard locked, I just pulled and held the charging handle back and tilted the ejection port towards the ground and let gravity clear the stoppage with the mag still inserted, the live round and empty case came out, then I released the charging handle and resumed shooting. It is a possibility that this was a bad round; I'll give it the benefit of the doubt. On this same match, and the following stage, after I took my last shot of the stage and went to clear the gun, a live round and empty case fell out. So I am not 100% sure this was a malfunction or where the empty case came from, but it is very possible I had a stoppage and just didn't get to realize it because my stage was over. The next and last stage of the match was fine. I am closely monitoring this setup with a round count log. I am sitting at 1,370 rounds with 1 malfunction and another questionable one, both after the 1,300 round count.
I'll let you know how it does going forward. I am using a carbine buffer tube, carbine spring, and carbine buffer, so there are no excuses, and it is exactly what CMMG recommends and sells the full rifles with. Edit: I am using the 9ARC endomags. |
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Posted: 11/17/2019 8:58:05 PM EDT
[#37]
Part 2/2
Recoil: I shot it next to my range's CZ scorpion and even had the range staff put some rounds through it. Everyone was blown away at how soft and flat this thing shot. I had a COMPLETELY NEW shooter with me who was nailing the 6" plates in the back with ease. "Dude this is like a real life video game" - his words. Holy shit amphibian you nailed it with this combination. The contrast was like getting nudged on busy subway vs getting punched in the shoulder. You can feel the bolt moving back and forth, it's very gentle. Supressor use: I shoot rifles lefty because of an eye issue, I was very pleased with the amount of gas coming to the face. My beretta m9a3 is significantly worse to shoot with regards to gas and debris. Accuracy: I have neither a proper optic, bench rest, or good shooter  to test accuracy with. But I sat down and leaned against the counter and did my best. But I put a few mags of various ammo sitting down with the rifle braced against the counter. I'm not a precision shooter by any means. The HST consistently printed the smallest group, best was 1" x 1.25" distance of 50ish feet. Speer 147s were second best and the suppressor tightened up the groups. A better shooter with a better optic and rest would do better ;).
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Posted: 11/18/2019 7:44:21 AM EDT
[#38]
Quote HistoryQuoted:
Part 2/2 https://i.imgur.com/ALwR3LT.jpg Recoil: I shot it next to my range's CZ scorpion and even had the range staff put some rounds through it. Everyone was blown away at how soft and flat this thing shot. I had a COMPLETELY NEW shooter with me who was nailing the 6" plates in the back with ease. "Dude this is like a real life video game" - his words. Holy shit amphibian you nailed it with this combination. The contrast was like getting nudged on busy subway vs getting punched in the shoulder. You can feel the bolt moving back and forth, it's very gentle. Supressor use: I shoot rifles lefty because of an eye issue, I was very pleased with the amount of gas coming to the face. My beretta m9a3 is significantly worse to shoot with regards to gas and debris. Accuracy: I have neither a proper optic, bench rest, or good shooter to test accuracy with. But I sat down and leaned against the counter and did my best. But I put a few mags of various ammo sitting down with the rifle braced against the counter. I'm not a precision shooter by any means. The HST consistently printed the smallest group, best was 1" x 1.25" distance of 50ish feet. Speer 147s were second best and the suppressor tightened up the groups. A better shooter with a better optic and rest would do better ;).Quote HistoryQuoted:
Part 2/2 https://i.imgur.com/ALwR3LT.jpg Recoil: I shot it next to my range's CZ scorpion and even had the range staff put some rounds through it. Everyone was blown away at how soft and flat this thing shot. I had a COMPLETELY NEW shooter with me who was nailing the 6" plates in the back with ease. "Dude this is like a real life video game" - his words. Holy shit amphibian you nailed it with this combination. The contrast was like getting nudged on busy subway vs getting punched in the shoulder. You can feel the bolt moving back and forth, it's very gentle. Supressor use: I shoot rifles lefty because of an eye issue, I was very pleased with the amount of gas coming to the face. My beretta m9a3 is significantly worse to shoot with regards to gas and debris. Accuracy: I have neither a proper optic, bench rest, or good shooter to test accuracy with. But I sat down and leaned against the counter and did my best. But I put a few mags of various ammo sitting down with the rifle braced against the counter. I'm not a precision shooter by any means. The HST consistently printed the smallest group, best was 1" x 1.25" distance of 50ish feet. Speer 147s were second best and the suppressor tightened up the groups. A better shooter with a better optic and rest would do better ;).My beretta m9a3 is significantly worse to shoot with regards to gas and debris. |
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Posted: 11/18/2019 7:46:38 AM EDT
[#39]
Quote HistoryQuoted:
I got all the way to approx 1,300 logged rounds without a malfunction across 10 different matches. Last match, match #10, I got a failure to eject. It was easy to clear since it didn't get hard locked, I just pulled and held the charging handle back and tilted the ejection port towards the ground and let gravity clear the stoppage with the mag still inserted, the live round and empty case came out, then I released the charging handle and resumed shooting. It is a possibility that this was a bad round; I'll give it the benefit of the doubt. On this same match, and the following stage, after I took my last shot of the stage and went to clear the gun, a live round and empty case fell out. So I am not 100% sure this was a malfunction or where the empty case came from, but it is very possible I had a stoppage and just didn't get to realize it because my stage was over. The next and last stage of the match was fine. I am closely monitoring this setup with a round count log. I am sitting at 1,370 rounds with 1 malfunction and another questionable one, both after the 1,300 round count. I'll let you know how it does going forward. I am using a carbine buffer tube, carbine spring, and carbine buffer, so there are no excuses, and it is exactly what CMMG recommends and sells the full rifles with. Edit: I am using the 9ARC endomags. |
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Posted: 11/18/2019 8:20:27 PM EDT
[#40]
I wanted to share something I experienced recently with my third 9mm Guard barrel, this one in 5".
I own (3) 9mm Guard barrels, a 16" which is a spare, a 16" that was cut down and rethreaded to ~11", and now the most recent a 5" that was cut down to 4". This new 5" barrel is having a "tight" chamber issue, meaning rounds (including several factory offerings) are engaging the rifling upon chambering. You can feel the bolt get stuck when trying to clear a live round of out the chamber and requires a small assist from a mortar sequence to get the bolt back. There are clear signs of a rifling mark ring on the projectile when the live round is extracted. I also plunk tested this 5" barrel side by side with my other 2 barrels, and the 5" fails the plunk tests with everything including factory rounds, while the other 2 do not. This could explain some accuracy inconsistencies I was seeing at 25 and 50 yards, but I do not know for sure until I get this chamber fixed. I contacted CMMG and they do not want to warranty the barrel because I voided the warranty by cutting and rethreading, which has nothing to do with the chamber, but that doesn't matter to them and they clearly don't want to own the responsibility; whatever, I'll move on! They did however recommend I "flex hone" the chamber, whatever that means. I reached out to Macon Armory to see if they can help. In this post I wanted to point out a few things: -CMMG's customer service (however you all want to judge it) -CMMG's quality control on these barrels -To point out that this could be a factor if you are having accuracy issues -And test fire your shit before you go out modifying it. Do not assume CMMG manufactured it correctly. Edit: By the way, the 5" barrel cut down to 4" cycled flawless. I didn't shoot it too much w/o a can but it had no cycling malfunctions unsuppressed. The majority of the shooting was done suppressed and it had no cycling malfunctions either. |
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Posted: 11/18/2019 8:35:20 PM EDT
[#41]
will be interested to see how you fix your short chamber...
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Posted: 11/18/2019 9:20:52 PM EDT
[#42]
Quote HistoryQuoted:
I wanted to share something I experienced recently with my third 9mm Guard barrel, this one in 5". I own (3) 9mm Guard barrels, a 16" which is a spare, a 16" that was cut down and rethreaded to ~11", and now the most recent a 5" that was cut down to 4". This new 5" barrel is having a "tight" chamber issue, meaning rounds (including several factory offerings) are engaging the rifling upon chambering. You can feel the bolt get stuck when trying to clear a live round of out the chamber and requires a small assist from a mortar sequence to get the bolt back. There are clear signs of a rifling mark ring on the projectile when the live round is extracted. I also plunk tested this 5" barrel side by side with my other 2 barrels, and the 5" fails the plunk tests with everything including factory rounds, while the other 2 do not. This could explain some accuracy inconsistencies I was seeing at 25 and 50 yards, but I do not know for sure until I get this chamber fixed. I contacted CMMG and they do not want to warranty the barrel because I voided the warranty by cutting and rethreading, which has nothing to do with the chamber, but that doesn't matter to them and they clearly don't want to own the responsibility; whatever, I'll move on! They did however recommend I "flex hone" the chamber, whatever that means. I reached out to Macon Armory to see if they can help. In this post I wanted to point out a few things: -CMMG's customer service (however you all want to judge it) -CMMG's quality control on these barrels -To point out that this could be a factor if you are having accuracy issues -And test fire your shit before you go out modifying it. Do not assume CMMG manufactured it correctly. Edit: By the way, the 5" barrel cut down to 4" cycled flawless. I didn't shoot it too much w/o a can but it had no cycling malfunctions unsuppressed. The majority of the shooting was done suppressed and it had no cycling malfunctions either. https://www.ar15.com/forums/ar-15/Thoughts-on-the-CMMG-Guard-/15-713060/&page=20#i7946025 As a side note, I also got a custom SS CMMG RDB made and it works fine but I haven't had time to group it yet. |
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Posted: 11/19/2019 8:29:38 PM EDT
[#43]
CMMG reached back out to me after I replied to their reply.
After some back and forth, they have offered to take a look at it. But they cannot promise they will be able to replace it due to company policy by the voided warranty, if they cannot fix it. They did mention they may be able to give me a discount on a new one if it comes to that. But we will see. Macon Armory has not responded yet. @amphibian, I do not have the confidence, nor the experience, to buy a finishing reamer and do the work myself and not fuck it up. If you guys know of someone else that I can send this barrel for this type of work, let me know. I'd like to have options just in case. Thanks for the help. |
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Posted: 11/19/2019 9:07:34 PM EDT
[#44]
Quote HistoryQuoted:
CMMG reached back out to me after I replied to their reply. After some back and forth, they have offered to take a look at it. But they cannot promise they will be able to replace it due to company policy by the voided warranty, if they cannot fix it. They did mention they may be able to give me a discount on a new one if it comes to that. But we will see. Macon Armory has not responded yet. @amphibian, I do not have the confidence, nor the experience, to buy a finishing reamer and do the work myself and not fuck it up. If you guys know of someone else that I can send this barrel for this type of work, let me know. I'd like to have options just in case. Thanks for the help. I did mess up a custom SS barrel with a finishing reamer as I didn't realize how much softer SS is vs the nitrided CMMG barrel. Deadshot barrels is who I used to make me the custom SS CMMG RDB barrel. I also sent him some of my reloads with no primer or powder so he could ream it out so that no rounds would get stuck and he did a great job. |
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Posted: 11/19/2019 9:43:06 PM EDT
[#45]
Quote HistoryQuoted:
My partner makes barrels for other manufacturers and he fixed several barrels for me with finishing reamers by hand. He told me not to use any power tools. As mentioned in the other thread, I tried a Clymer reamer and it didn't remove enough material to fix the issue. My partner was using a Manson reamer and I thought they were all the same and save a few bucks so I bought the Clymer first. Then I bought the Manson later to fix it. I don't think you can mess it up. I did mess up a custom SS barrel with a finishing reamer as I didn't realize how much softer SS is vs the nitrided CMMG barrel. Deadshot barrels is who I used to make me the custom SS CMMG RDB barrel. I also sent him some of my reloads with no primer or powder so he could ream it out so that no rounds would get stuck and he did a great job. Where did you buy the Manson reamer from? Thanks |
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Posted: 11/19/2019 10:02:04 PM EDT
[#46]
Brownells
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Posted: 11/20/2019 11:51:45 PM EDT
[#47]
Quote HistoryQuoted:
CMMG reached back out to me after I replied to their reply. After some back and forth, they have offered to take a look at it. But they cannot promise they will be able to replace it due to company policy by the voided warranty, if they cannot fix it. They did mention they may be able to give me a discount on a new one if it comes to that. But we will see. Macon Armory has not responded yet. .......resend to my personal [email protected] me a phone if you can...I have to roadtrip to my laser cutter and then to heat treaters tomorrow......so I'll have about 5 hours total in the truck tomorrow that I can give ya a call and discuss....:-)
I'm pretty sure the guard barrels are nitrided so a Manson reamer is just gonna die a squealing death if you try reaming......I have chamber hones and will try that for you, but as they primarily polish, I wouldn't hold my breath for fear of turning blue. If that doesn't work it will entail running a carbide reamer in and cuttting the lead into rifling without setting the chamber shoulder any deeper. CAN be done, but kinda tricky 
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Posted: 11/21/2019 11:39:38 AM EDT
[#48]
Quote HistoryQuoted: What was the email address....I have been basically by myself for a while from the office side for a couple of months......and have devoted all my time to keeping up with orders....honestly don't remember seeing your email, then again I have been stretched so thin I could have answered and don't remember...... .......resend to my personal [email protected] me a phone if you can...I have to roadtrip to my laser cutter and then to heat treaters tomorrow......so I'll have about 5 hours total in the truck tomorrow that I can give ya a call and discuss....:-)
I'm pretty sure the guard barrels are nitrided so a Manson reamer is just gonna die a squealing death if you try reaming......I have chamber hones and will try that for you, but as they primarily polish, I wouldn't hold my breath for fear of turning blue. If that doesn't work it will entail running a carbide reamer in and cuttting the lead into rifling without setting the chamber shoulder any deeper. CAN be done, but kinda tricky |
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Posted: 11/21/2019 8:07:59 PM EDT
[#49]
Quote HistoryQuoted: What was the email address....I have been basically by myself for a while from the office side for a couple of months......and have devoted all my time to keeping up with orders....honestly don't remember seeing your email, then again I have been stretched so thin I could have answered and don't remember...... .......resend to my personal [email protected] me a phone if you can...I have to roadtrip to my laser cutter and then to heat treaters tomorrow......so I'll have about 5 hours total in the truck tomorrow that I can give ya a call and discuss....:-)
I'm pretty sure the guard barrels are nitrided so a Manson reamer is just gonna die a squealing death if you try reaming......I have chamber hones and will try that for you, but as they primarily polish, I wouldn't hold my breath for fear of turning blue. If that doesn't work it will entail running a carbide reamer in and cuttting the lead into rifling without setting the chamber shoulder any deeper. CAN be done, but kinda tricky |
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Posted: 11/22/2019 6:40:02 PM EDT
[#50]
I've got a Stern Defense 9mm mag block and an 8" CMMG Guard upper I assembled. With the upper mounted, the mag block will not insert all the way. With the upper removed, the mag block will insert properly. What do I need to modify so it all works properly?
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