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Posted: 6/11/2018 11:39:34 PM EDT
| The Guard bolt and barrel setup really interests me as well as the QC10 side charging upper. Any issues running these two together? I'm fine with tuning issues just really want to make sure there are no show stopping issues. As far as a lower goes, I'm still up in the air. QC10 Colt lower or mag block in an extra Aero M4e1 lower? |
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Quoted: As far as a lower goes, I'm still up in the air. QC10 Colt lower or mag block in an extra Aero M4e1 lower? No data on using with the side charger unfortunately.... |
| Ok cool. In that case, you can't go wrong with either lower. Functionally, I've tried both QC10 and mag block with the Guard and they work about the same. Just depends if you want the classic Colt SMG look or more refined sleek look of the QC10. QC10 would obviously look good with their side charger but then again I'm a sucker for old school. |
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I installed the Guard system in a Gibbz Arms side charging 9mm upper coupled with a NFA lower (Glock mag). The dummy gas key of the Guard BC had to be cut back with a Dremel cut off wheel to clearance the charging handle/modified cam pin of the Gibbz system. I have several Gibbz uppers and like their setup a lot.
Two comments on the Guard system: 1) The blowback ejector needs to be removed. On 9mm ARs, the ejector also serves as a mag stop. With it removed, be careful not to over-insert the magazine. 2) The Guard system takes a few hundred rounds to break in. Expect FTEj (stovepipe) malfunctions during this period. |
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Quoted:
Links to the other thread? This has my interest. https://www.ar15.com/forums/ar-15/Thoughts-on-the-CMMG-Guard-/15-713060/&page=11 |
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Quoted:
I installed the Guard system in a Gibbz Arms side charging 9mm upper coupled with a NFA lower (Glock mag). The dummy gas key of the Guard BC had to be cut back with a Dremel cut off wheel to clearance the charging handle/modified cam pin of the Gibbz system. I have several Gibbz uppers and like their setup a lot. Two comments on the Guard system: 1) The blowback ejector needs to be removed. On 9mm ARs, the ejector also serves as a mag stop. With it removed, be careful not to over-insert the magazine. 2) The Guard system takes a few hundred rounds to break in. Expect FTEj (stovepipe) malfunctions during this period. Did you use a 9mm/pistol specific upper? If so, I don't understand where the 'modified cam pin' would come into play? Also did you have issue with the smaller ejection port? If you meant you use a 556 style side-charger that would make WAY more sense. If so, I'm curious if you could snap a pic of the mods you had to do as I'd like to run a similar setup. Thanks! |
| I used the Gibbz 9mm upper. The issue is that the key used on the Guard bolt carrier interferes with the Gibbz cam pin. I am fortunate to live close to Gibbz, and they looked at it for me. All it took was to cut off the front portion of the key with a Dremel cutoff wheel. I will post a photo when I get a moment. |
| Qc10 side charging upper was ordered on the July 4th sale. AERO Atlas rail came a couple weeks ago. It feels like a cheese grater. It's back to SLRs or maybe the UTG Pro. I already milled off the extensions that extend over the upper receiver. I ordered the Colt QC10 lower today. When I go to pick that up my Form 1 can is being submitted. Next is the bolt and barrel. Then the trigger is scheduled to be ordered before the Christmas deadline for MBTs. I really wanted this done before I put all the steel away for the year but not enough sales and this one has turned into one expensive gun. |
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Quoted:
I used the Gibbz 9mm upper. The issue is that the key used on the Guard bolt carrier interferes with the Gibbz cam pin. I am fortunate to live close to Gibbz, and they looked at it for me. All it took was to cut off the front portion of the key with a Dremel cutoff wheel. I will post a photo when I get a moment. I have an NFA side-charger (same design apparently) but obviously no cam pin. I'm wondering if I just buy the G4-style cam pin if I can use it. Trying to avoid having to buy a whole new upper. Or did you have a G4 (556) side-charger and they just cut the gas key to make it work. G9: 
vs. G4: 
9mm blowback bolt, notice no cam pin: 
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Very curious if you guys are able to get the Gibbz 9mm upper working with the CMMG Guard.
My NFA C5 upper wont work with it due to not having any cam pin cuts. Does the Gibbz G9? Or is the G4 with a cam pin swap & guard gas key mod the answer? Wanna post some photos of what they did? Thanks! |
| I had RMWXTREME.COM build a DI 9mm (uses standard 223 bolt carrier and modded 223 bolt or 5.45) with a Gibbs 9mm upper receiver and no issues do so. Their G9 upper was/is the only 9mm upper that is able to use a gas system. It looks like with their 9mm upper it is setup as 223 but with a 9mm sized ejection port. |
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Recieved my Gibbz G9 after a month of waiting. A few things; The NFA C5 side charger seems to have the 5.56 size ejection port. I didnt realize this until comparing it to the G9. The C5 upper is also made by Gibbz. With the G9 upper there is plenty of clearance for the MP5 magazines with no modification. Adding the G4 gibbz cam pin to the CMMG guard BCG was a bit tight. I found that I did not need to trim the "gas key" at all but I did need to grind off maybe 1mm of the bottom corner to allow the new cam pin to rotate without contacting it. Was able to get 100% reliable feeding/ejection by racking the handle. Ill add pics later |
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FYI, I just got an email today saying that the G9 upper are back in stock and have a few mods to them, one being to work the the CMMG guard stuff. It said "CMMG guard lower" in the email but I think the wordage was just incorrect as it linked to the barrel/BCG combo.
We're excited to have this new batch of G9 uppers in stock! We've made some key improvements to our G9 uppers to make them compatible with more options in the PCC world.
First of all, our G9 uppers now have the necessary cuts to work with MP5 lowers! We can't wait to see your builds with our G9 uppers on MP5 lowers! Second, our G9 uppers have the cut out for a cam pin so that it is compatible with the CMMG Guard lower. CMMG uses a delayed blow back system. You can check it out here. |
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