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  1. #1
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    Default cmmg lower parts kit review...........

    You guys may have read that I picked up a lower the other day. I got a new stag. They have been a solid lower to build with little to no deviation in quality, for me anyway. I was itching to get started so I broke down and stopped at Beikirchs to see what fodder they had. I saw a few 2 stage triggers a DPMS kit and a CMMG kit along with some stocks and other what nots. I have heard a few good posts on the CMMG kits so I got it. it was $7. cheaper than the DPMS kit. I am a cheap @$$. I figure that when I order my AR kit that I can put the new lower parts group away for spares.


    The color coded bags in the box were cute. They let you know what group of parts were in each bag. There is a little card that details the contents of each bag. It also comes with a bonus sticker!
    Everything looked OK. No problems puting it together. The trigger is a typical standard trigger feel and pull weight. I do have one problem, that I have not come across in 14 builds. After some measuring of parts the trigger gaurd flops around ( there is some wiggle toward the push detent ). I have not had this happen before. It seams that the front trigger gaurd hole is a little bigger that the other 2 stags that I have. The other problem I had was the PG would not seat. I have a few spare so I there a different one on it was beauteous! I did not take the time to trim plastic or see it the safty detent spring hole in the grip was the proper depth. It did not fit. What more can I say.

    I just need to figure out what I want to build from here on out. Maybe some red furnature with a short stock and call it the wifes/daughters rifle.

  2. #2
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    I'll be putting together my first lower very soon. The parts kit I got has a CMMG label on it but I don't know if it really is. It was given to me by a very generous Gunboards member. It came in a round plastic tube. I separated the parts myself into groups and bagged them in little zip locks.
    I'll let you know how it goes. We are going to put a over moulded grip on it so if like Mike's the grip don't fit it's NBD.
    Motor

  3. #3
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    Florida Mike,

    Easy solution, mail the receiver to Stag and ask they fix the issue. They have been around a long long time and are not a fly by night unknown parts maker. They will cure your problems (probably using their own parts) or replace the receiver if its "out of spec".

    You can do that and spend ten bucks in mailing costs or live with the issues on that receiver the rest of your life and be annoyed every time you pick the weapon up. Stag is a quality product, you were wise to buy that level of lower receiver, so take advantage of buying quality and send the receiver off to Stag and be happy.

  4. #4
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    Mike,
    I did misunderstand you OP. Actually misread it. I thought the problem was with the trigger guard it self. That is a funny coincidence because I put my first lower together today with the aforementioned lower parts kit and all went well except for 3 items.
    1) The trigger guard pin was a press fit in the guard as well as the lower. My other AR is not like that. The split pin on it is a slip fit in the guard.
    2) The bolt release spring had a flair on one side and would not fit into the recess.
    3) The safety would not switch back to safe from fire under the full pressure of the spring.

    I was able to overcome all 3. It's nice being a machinist and have a friend who is a gunsmith.
    Motor

  5. #5
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    I made A vidoe presentation for you to illistrate the problem.



    thanks motor!
    Last edited by Florida Mike; 05-01-2012 at 07:54 PM.

  6. #6
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    I see. So it must be either a oversize hole in the lower or the pin is undersized. You probably have other actions to compare it too. I'll take a close look at mine and measure the 2 parts.
    What about my build and the 3 issues I listed. Have you seen anything like it before?
    Motor

  7. #7
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    sounds like my problem in a way on #1

    either the hole in the receaver is out of spec or the role pin is too small diameter. What lower did you use?

    #2 the only spring with a flare on it belongs to the trigger disconnector spring. the bolt catch spring and disconector spring are of simulare size. It sounds like you may have accidently swaped them.

    #3 This will happen if the gun is in the un-cocked or hammer up position the safty will not go into the safe positon, until the hammer is pulled back to the cocked posion.
    Last edited by Florida Mike; 05-01-2012 at 08:14 PM. Reason: I cant spel

  8. #8
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    Mike,
    1) I didn't like that the roll pin was a press on both the lower and the guard. It don't make sense to have a pivoting part that can't pivot. I drilled my trigger bigger so the roll pin would slip through it. (This is how it is on my Rem. VTR) The front hole is .125" and the pin is .115". So now my trigger guard fits kind of like yours now.

    2) I have a spare trigger so I will have to look at that. I trimmed off most of the flair and bent the last half coil inward. The bolt release feels the same as on my Rem. so I don't think I'll be messing with it unless it's a must.

    3) It turned out that the edge leading out of the "fire" detent was sharp where the other side had a slight corner break. I was able to break the corner with a pencil shaped stone in my Dremel. Now it's still a little resistant but is usable and will get better with use.

    The trigger guard thing is still a puzzle. Should the roll pin be tight in the guard or not? I'm convinced it is supposed to be a press fit in the lower.
    Motor

  9. #9
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    this is the first triggger gaurd that was loose for me all of mine have been on the tight side. I like it that way. no rattle.

  10. #10
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    I looked at my other "stock trigger" and the disconnect spring does not have a flair and it looks longer than the bolt catch spring. It may be heavier wire too. I used the schematic on Midway USA's site to match up the parts. I guess it's just one of those mysteries for now.
    Motor
    I did find one on the web (dissconnect spring) that looks like the one I put in the bolt catch. I guess even the "stock" triggers are not all the same.
    Last edited by Motor; 05-01-2012 at 10:32 PM.

  11. #11
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    http://www.youtube.com/watch?v=p6AZ1jxJGRM at 50 seconds it shows the flared spring. I have bungled this up once.

  12. #12
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    [QUOTE=Motor;2135010]I looked at my other "stock trigger" and the disconnect spring does not have a flair and it looks longer than the bolt catch spring. It may be heavier wire too. I used the schematic on Midway USA's site to match up the parts.I guess it's just one of those mysteries for now.
    Motor

    OH WELL. All above in red is incorrect!!
    Numrich gives a detailed description of the disconnect spring. I took the one out of my spare trigger and sure enough, it IS flared.
    Turns out what I thought was going to be a nightmare wasn't too bad. I used a .080" pin punch to back out the bolt catch pin and put the correct spring in it. Then used my spare disconnect spring to replace the one I chopped.
    I can't believe I made that mistake. Thanks Mike, for steering me in the right direction. You can't see the flair in the schematic because it's down in the trigger but I should have known better and did my research before taking the wire cutters out. Live and learn.
    Motor

  13. #13
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    Glad it worked out for you.

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