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Posted: 6/11/2012 6:11:50 PM EDT
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OK Bear with me guys I'm new at this! Got a RRA NM 2 stage trigger I'm trying to install in a DPMS AR15. I cannot get the hammer to catch. I've got the thing pushed down as far as it will go & I put the punch in & it works but as soon as I put the pin in it won't catch. So I figured bad product & I'll send it back. Tried to put the original in & same problem!! WTF????? Any help would be greatly appreciated!! I am ready to toss the whole thing in the garbage!!!
BW 
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What is so hard to get, First, make sure that the disco is moving freely (just spring loaded) in the trigger. Install the trigger with the trigger pin and the spring legs forward on the bottom of the receiver void. Next install the hammer with the hammer spring legs coming out the bottom side of the coil, and with the spring legs on top of the trigger pin. Without touching the trigger, cock the hammer back until the RRA hammer front sear engauges the front trigger sear. Also note as the hammer comes back, the trigger is going to be moved slightly rearward so the hammer sear can get past the trigger front sear. Now grab the hammer, pull the trigger back for the hammer to be released from the trigger front sear, then cock the hammer back again while still holding the trigger back. The hammer rear sear will now push the disco back so it can get past the disco sear, and with the trigger still held back, the disco is now holding the hammer until reset. On rest, stick your hand in front of the hammer to catch it the trigger front sear does not catch the hammer, and release the trigger. The hammer retention is now passed from the back sear off the disco, to the front sear of the trigger. Now the point of joy or not. With your hand still in front of the hammer to catch it before it crashes into the front of the receiver, start to slowly pull the trigger. There is going to be a tad amount of creep, the the disco will make contract with the rear hammer sear just above the sear edge. If the trigger is set right, then as you get this engagement to increase the tension pull (the second stage set of the trigger, any further pull of the trigger is going to release the hammer. As for problems with the trigger, Disco is not free moving or you did not lube the FCG parts before installing them If you got the FCG used, then the disco sear spring may be worn out and why you are not getting the second stage, You have the wrong FCG for your receiver, hence the receiver pin size is .154, and you have a old style colt pin size of .174 FCG that you are trying to using on the smaller mil spec pins (read FCG channel sizes needs to make the pins in the receiver. The sides of the selector are blocking the tail of the trigger (selector slot too narrow) or you forgot to install the pistol grip bolt washer, and now the pistol grip screw is protruding into the bottom of the receiver void, and not allow the trigger to come back to full rest. Also, don't forget to install the selector detent pin point upwards, and the grip spring in the grip channel for it so when the grip is installed, it to put spring pressure on the selector detent so it retains the selector correctly. http://www.ar15.com/content/guides/assembly/lower/ |
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Quoted:
Trigger is new from Valhalla Tactical. Slot is plenty wide enough. Grip washer is on. Pin size is correct. Selector installed correctly. Now> Why would the original trigger not work either??? Show me a photo of the NM FCG installed in the lower (straight down photo). As for the old trigger, going to take a stab at it, but best guess, you did not have the disconnector spring installed, and why the disco did not retain the bolt when you have the trigger pulled back. If the question comes down to why it would not retain the hammer with the trigger at rest, with the trigger group uninstalled, make sure that the top of the pistol grip bolt is not protruding up in the bottom of the receiver cavity (read if you changed out pistol grips, then the depth of the channel for the bolt in the new grip may be shorter than the old one, causing the top of the grip bolt to protrude into the bottom of the receiver. If this is found, then the grip bolt will need to be shortened). Hence, with the grip screw protruding up in to the bottom of the lower receiver cavity, then it does not allow the trigger to return back to it's normal at rest position to allow the trigger front sear on either the old or NM fire control group to get into the correct position to retain the hammer. Also, a dead give away that you have this problem with the trigger not returning to it's normal at rest positon, with the hammer removed, you still will not be able to move the selector into the safe position (back tail of the trigger up off the back of the receiver, and blocking the selector from turning to safe). P.S, being that this is a DPMS receiver, there should be no trigger adjustment screws for take up in the receiver, but double check to see if you have a take up adjustable grip bolt in play. If you do, then it will have a small allen set screw in the center of the grip bolt that you may have to readjust via an allen wrench up through the center bottom of the bolt. |
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Dude, really?????
Look at the photo I added to this post. the trigger shown in each group only works with that hammer shown in the same group . In the photo's of yours with parts installed, you have a standard (non NM) hammer with a NM trigger and it ain't going to work with these parts installed that way. So leave the NM trigger in the receiver, pull the standard hammer out, install the NM hammer back in, and all will be good in the world. Standard FCG and it's parts, 
NM FCG, and its specific matching parts,
so again, each hammer/trigger/disco has to be used with it's own FCG specific parts alone and not swapped between the two or another NM Fire control group. The standard selector, it's detent, and the detent spring work for both shown fcg's, so you can use those in either of the groups shown. |
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So I'm guessing with the right parts installed, this whole topic is now mute, with the problem solved?
And to beat you to the punch, if down the road you lose the increase tension of the second stage point, it's the disconnector spring that went weak/soft, and just the disco spring that needs to be replace. |
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