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View Full Version : Just installed a CMMG 2 stage trigger


savasyn
09-03-2008, 7:25 PM
I needed to get a decent 2 stage trigger for my reg'd AR as I've been using it for 3gun and the stock trigger was woefully inadequate. The rub came from having a 9mm upper for it so I couldn't go with the basic RRA style without problems. Luckily, I found the relatively new CMMG trigger that doesn't cost too much more than the RRA and has take up and over travel set screws as well as brass pin bushings as bonus features. With the round shaped hammer, it was supposed to work with any upper.

As I had not built my own OLL(Randall did mine), I had never worked on an AR trigger before. I was very happy to find it incredibly easy. The only weird part was that I had to remove the safety to get the old trigger out but had to have the safety back in before installing the new one. Whatever...

Anyway, I was immediately impressed with how much better it was than the stock garbage. The take up was decently short and the release was very light and crisp. And this was before I installed the set screws!

Once I had verified functionality, I followed the instructions for the set screws. You start with the front one(over travel) and then do the rear(take up). You can remove 100% of the take up if you want to. That basically gets you a very light single stage trigger. I actually found it a bit scary when there was no take up at all. Seems that you'd get a lot of doubling and accidental bump firing that way. I backed it off 1/2 a turn so there is some take up, but not much. It still feels really light and that I'll sure it'll take some getting used to.

Once back together, I brought out my off-list that has the RRA trigger in it and verified that the CMMG is indeed lighter on the 2nd stage. The set screws really make it feel like a higher-end, more precise unit as well. I'm looking forward to taking it out for a test drive this weekend. If that happens I'll report the results in this thread.

Oh yeah, it DOES work with the 9mm upper! I ignored that small, nagging inner voice saying that it might jam up and went ahead and installed the 9mm upper and worked the action. Sure enough, smooth as ever, no problem. So there you go, if you have a 9mm upper and want a nice trigger, the CMMG is a good way to go.

Summary of my experience so far:
*Easy to install
*Easy to adjust
*Wow, light and crisp release!
*Works with RRA 9mm uppers(possibly all of them, but I only have an RRA)

apbrian112
09-03-2008, 7:56 PM
i'm guessing that this is in a non-ramped bolt? good to know for those planning on or already building a colt-style 9mm AR.

how much difference was there in the weight of the pull? i have a RRA 2-stage but never checked it.

savasyn
09-03-2008, 8:49 PM
Correct, non-ramped bolt. That said, I'd still like to get the bolt ramped as I've read the non-ramped bolts are very hard on the hammer pin holes due to the rapid reset speeds.

I can't say exactly the difference in trigger weight between the RRA and the CMMG, but it feels somewhere between 1/2 and a full pound. That's purely a guess, though. The new one is probably 4-5lbs lighter than the stock trigger.

aplinker
09-03-2008, 9:44 PM
Excellent, thanks for the write-up.

I haven't had the resources or need to try one out, but from all accounts they're looking good.

Appreciate it.

tenpercentfirearms
09-03-2008, 11:08 PM
I think I am going to order a few dozen and test one on my 9mm. I better do this tomorrow.

Sydwaiz
09-04-2008, 7:16 AM
Sounds like I'll have to give it a try as well. I never did like the RRA 2 stage in my reg AR.

savasyn
09-04-2008, 8:35 AM
Sounds like I'll have to give it a try as well. I never did like the RRA 2 stage in my reg AR.

It's not that much different/better that I could recommend swapping out an RRA for the CMMG. If you really don't like the feel, you might consider one of the fancier, yet more expensive triggers instead. As I said above, they are pretty similar in feel with the edge going to the CMMG due to slightly lighter release and, of course, the adjustability. I don't know if it's worth the extra money to swap one for the other unless you want to use a 9mm upper on that lower.

That said, I'm sure you can sell the RRA unit and recoup some of the money if you decide to try the CMMG.

mike22ca
09-04-2008, 9:44 AM
Thats for the write up. Ive been curious about them myself since they just hit the scene and have a good reputation for quality. I myself started off with the RRA 2-Stage, maybe on the next build I'll start from the get go with a CMMG 2-stage.

jandmtv
09-04-2008, 9:59 AM
Nice write up! I have been eyeing the CMMG trigger for a while, but I was waiting for someone els to try it first :D

savasyn
09-04-2008, 10:13 AM
Thanks!
I still haven't shot it yet, but it sure feels great dry firing.

I have one potential concern in the back of my mind regarding the location of the over-travel set screw(front one). It sits right next to the front arm of the trigger spring and I had to move the spring arm over before I put the set screw in. My concern is that the spring arm might wiggle its way under the set screw thus preventing the trigger from being able to release. Unlikely, but I suppose it's possible.

I didn't find the over travel offensive before I added the set screw, so it wouldn't be the end of the world if I had to take the screw out, or even just loosen it up a bit if my concern became a reality.

The take up screw is the one that changes the feel of the trigger more, and it is not in a position to be obstructed, so it can happily stay put.

Mississippi
09-04-2008, 10:37 AM
Congrats and thanks for the write up. Let us know how it shoots.

EBR Works
09-05-2008, 9:41 AM
Thanks for the heads up on this item. I just ordered one for my DPMS Panther upper/Spikes lower in 7.62x39. I hope it is worth the extra $50 over the price of the RRA NM which I have been very pleased with on my other lower!

tenpercentfirearms
09-06-2008, 8:35 AM
I ordered 20 yesterday. As soon as they come in I will install mine on my RRA 9mm and go try it. I need an excuse to get some ragne time in.

a1fabweld
09-06-2008, 11:15 AM
I'll second the good review on the CMMG 2 stage trigger. I installed mine earlier this week along with some KNS anti rotation pins & it feels great. Install was straight forward with the provided instructions. I installed a JP trigger for a friend's AR-10 build last night & once adjusted, they feel very similar. Good product!

savasyn
09-06-2008, 11:45 AM
Out of curiosity, what is the advantage of the anti-rotation pins? Additionally, how do they work(mechanically, that is)?

I've seen that people use them, but never an explanation of why.

Thanks!

nobs11
09-06-2008, 12:14 PM
Out of curiosity, what is the advantage of the anti-rotation pins? Additionally, how do they work(mechanically, that is)?

I've seen that people use them, but never an explanation of why.

Thanks!

Basically an anti-rotation pin set links your hammer and trigger pins together so they stay put and don't back out or move under use.

Look at this and you'll get the idea:

http://cmmginc.secure-mall.com/shop/index.php?shop=1&cat=11

ironcross
09-06-2008, 12:20 PM
Out of curiosity, what is the advantage of the anti-rotation pins? Additionally, how do they work(mechanically, that is)?

I've seen that people use them, but never an explanation of why.

Thanks!

Well What I have read about them. The lowers or most of them are made out of aluminum, and sometimes the pins spin in place or move from left to right witch can take aluminum off it after a while. With the anti-walk it keeps the pins where they are suppose to be.