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Posted: 10/2/2014 12:26:47 AM EDT
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Hello,
I just got a 9mm upper for my 556 NFA lower. My guy finished my build today but said he was running into some issues with what he said hammer follow issues and it will not work with a 2 stage trigger. to fix the problem right now he installed a GI trigger and everything is working well.. I really like my after market triggers and had a RRA nm trigger installed in this lower. AFAIK its a RRA 9mm is a ramped bolt. So i guess my question is do you know if there is a after market trigger i can get to work with this bolt ? I have a geissele SSA and Super dymanic triggers in 2 of my other ARS i can try swapping or buy something new. If i am stuck using a GI trigger with this bolt i would prob rather get a 9mm dedicated lower and send a stamp off which i really rather not do but it is what it is. any info would be great. Thanks |
| I have a CMMG ramped bolt and an RRA 2 stage that I like to bump fire. When the rate of fire gets too high the hammer won't catch on the disconnector and it will follow the bolt forward causing it to not fire. I'm working on using a different buffer / spring combo. I haven't tried a different trigger yet. |
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I have used both the RRA bolt and the CMMG bolt. I like RRA stuff but the CMMG 9mm set up just seemed to work better. The CMMG bolt is factory ramped and I know they spent some time on getting it right to work with standard pattern triggers. It is just enough different than the RRA to be more tolerant of different trigger designs.
Free advice is worth just what you paid for it. |
| I tried running a New Frontier poly lower on a RRA 9mm upper w/ramped bolt and the trigger would not reset itself after firing but WOULD reset when hand cycled, never figured out why. Same lower functioned fine in 5.56, 7.62x39 and 5.45x39 uppers. My RRA 9mm upper started out on a RRA 5.56 lower w/single stage trigger and has always worked fine on that. |
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Quoted:
I tried running a New Frontier poly lower on a RRA 9mm upper w/ramped bolt and the trigger would not reset itself after firing but WOULD reset when hand cycled, never figured out why. Same lower functioned fine in 5.56, 7.62x39 and 5.45x39 uppers. My RRA 9mm upper started out on a RRA 5.56 lower w/single stage trigger and has always worked fine on that. Picture of said ramp and hammer... |
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I just finished my first 9mm build over the weekend. I am using a 5.56 SBR lower with a Hahn mag block. My bolt is a CMMG ramped bolt. I had a Giesselle SSA in the lower and during the function check would not reliable catch the disconnector and the hammer would follow the bolt forward. Pulled out the Giesselle and put a CMC trigger in and had the same issues. Started getting worried but figured that the shape of these two triggers may have something to do with how the bolt reacts with it as it re-cocks it on hits way to the rear so I decided to try the hammer the guns were designed around and put in a regular GI hammer/trigger group. Function check worked flawlessly and then went to the range. 500rds without a problem.
It appears to me that there is just not enough "meat" on the upper portions of the high end hammers to allow the bolt to fully engage the hammer with the disconnector. Some of our engineering savvy members may be able to explain it better. |
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Quoted:
I just finished my first 9mm build over the weekend. I am using a 5.56 SBR lower with a Hahn mag block. My bolt is a CMMG ramped bolt. I had a Giesselle SSA in the lower and during the function check would not reliable catch the disconnector and the hammer would follow the bolt forward. Pulled out the Giesselle and put a CMC trigger in and had the same issues. Started getting worried but figured that the shape of these two triggers may have something to do with how the bolt reacts with it as it re-cocks it on hits way to the rear so I decided to try the hammer the guns were designed around and put in a regular GI hammer/trigger group. Function check worked flawlessly and then went to the range. 500rds without a problem. It appears to me that there is just not enough "meat" on the upper portions of the high end hammers to allow the bolt to fully engage the hammer with the disconnector. Some of our engineering savvy members may be able to explain it better. This is correct. Hammer profile. My S3G would not reset. UZI profile hammer works fine. I think the ALG trigger will work. |
| I have a CMMG 9 pistol and tried to install a CMC trigger group. No go, it would fire 2 or 3 times than fail to reset. CMC said sometimes they work and sometimes not. That drop in was not designed for a 9 upper. Put std AR trigger in and it runs great. I just cannot pull the trigger fast enough. |
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