Good morning folks, I'm brand new here on AR15.com, but I have been reading a lot on here over the past year or so. I apologize if I miss some kind of educate, and I have done my best to not ask a question that has already been asked a million times. I first googled this and read multiple pages on your website and others, but could not find a similar problem.

I just tried installing an ALG Defense ACT trigger in my brand new Spikes Tactical lower. All parts are new, never fired or altered. Safety is a BAD-ASS, upper is BCM 16" mid length, BCG and charging handle are BCM as well. I double checked that the springs were all installed correctly, this is my first AR build, but after looking at tons of diagrams and pictures, I'm 99% sure I've got them in right. Here's the problem: With the upper removed, and the hammer in the "up" position, I manually cock the hammer. If I gently press it down so that only the lower part of the trigger sear surface engages the notch on the bottom of the hammer. This will hold the hammer down, and pulling the trigger releases it. However, if I push the hammer all the way down so the disconnect engages the hook on the hammer, the trigger does not fire. I must manually press on the rear tab of the disconnect with a punch, which releases it to the stage I mentioned before, where the trigger will release the hammer properly. I have tried this with the safety both installed and uninstalled. I also attached the upper and tried to pull the trigger, nothing happens. From looking at the trigger, hammer, and disconnect, when the hammer is stuck on the disconnect, and I try to pull the trigger, the disconnect actually moves further towards the muzzle, which obviously prevents it from firing. The way I understand it, the disconnect isn't even supposed to hold the hammer down except momentarily to give the trigger time to lock up, correct?

What am I missing here? Any help is greatly appreciated, I spent hours looking at diagrams and videos, but can't figure it out. Contacted ALG and explained my issue, they said to send the trigger back for them to look at it. Does this sound like a trigger issue or a lower receiver, or what? Oh, I haven't done any "bubba" mods on any of the parts either, everything is as it shipped from the factory. Thanks guys!

try turning the disconnector spring over.

Thanks, but I already tried that, it is in there correctly, I tried it both ways just to be sure.

it sounds like the recess the disconnector rides in is binding, like it is too tight. take the trigger apart and check the fit of the disconnector  in its groove. it must move freely over its entire travel, it sounds like it may be binding at the bottom.

Sounds like your pulling the trigger while its on the disconnector? This will keep it hooked on the disconnector. Not touching the trigger at all what happens when you press the hammer all the way down? Hooks on sear and the disconnector? Or just one? Which one?

The disconnector doesn't "momentarily" hold the hammer, it holds it as long as your holding back the trigger, you let go of the trigger it should fall off the disconnector and on to the sear.

Nope, releasing the trigger does not allow the disconnect to release the hammer. The only way to get it to release is by manually pressing on the rear of the disconnect.

Update: I contacted ALG and they are having me ship it back, should hear from them early this coming week. I'll repost once I hear from them. Thank you all so much for your help and advice, I really appreciate it.

Another thing to try, is to press the trigger shoe forward to see if the trigger spring has enough force to reset the trigger off of the disconnect.

Yes I did try pushing the trigger forward, that would not release it either.

Are you engaging the disconnector with the hammer with the trigger pulled back?
That's the only way it should engage under normal conditions.
If you are forcing it down with the trigger forward, you are creating an abnormal condition.

A proper function check you pull the trigger back, engage the hammer with the disconnector, then relase the trigger and the hammer should catch on the trigger sear.

When you install the disconnector spring, are you pressing the spring (large end down) all the way to the bottom of the recess in the trigger?

If the spring is not positioned at the bottom of the recess in the trigger, the disconnector may hang.

So update everyone: ALG shipped the trigger back, they said it functioned fine in their lowers. Placed it back in mine, same problem. There is no material in my lower from the grip screw that is causing this malfunction. What should I do next? Is it possible that I need to file just a bit of material from the inside of my lower? Where should I start? Thanks!

Ok here are a few pictures. I had trouble getting a good one so I have a few here. Switching between safe/fire does not appear to move the trigger or disconnect. http://s1285.photobucket.com/user/isaacgraham1/slideshow/Mobile%20Uploads

I have the same issue with the same trigger.  I am using an 80% lower with KNS pins.  Installed in the receiver there is about .02 to .05 of an inch of interference between the disconnector and the hammer hook. At first I thought the FCG pin holes were too close together, as the KNS pins are a snug fit to the lock bar, but now I am not so sure.  I have considered shortening the nose of the disconnector,  deepening the spring notch in the disconnector, and putting a very thin shim under the foot of the disconnector.  


Edit: Those pictures match my situation perfectly.

http://i1285.photobucket.com/albums/a590/isaacgraham1/Mobile%20Uploads/image_zpse8bbd95a.jpg
http://i1285.photobucket.com/albums/a590/isaacgraham1/Mobile%20Uploads/image_zpsa6af81dc.jpg
http://i1285.photobucket.com/albums/a590/isaacgraham1/Mobile%20Uploads/image_zps9fca0473.jpghttp://i1285.photobucket.com/albums/a590/isaacgraham1/Mobile%20Uploads/image_zps592dd655.jpg
http://i1285.photobucket.com/albums/a590/isaacgraham1/Mobile%20Uploads/image_zps1fc53cb4.jpg

Honestly I don't have much in the way of tools. Not even sure if I have a metal file.

Oh and I do not have another disconnect on hand unfortunately.

Thanks, Ike, for continuing to post on this.

I am feeling like the remedial one tonight, so let me think through this step by step.

Clearly, there is a geometry problem with the assembly.

ALG has inspected this fire control group and sees no tolerance issues, so that points to either receiver pin channels (receiver problem) or trigger/disconector misalignment.  ALG could be wrong but let's assume, temporarily, that the fire assembly parts are all in spec.

So, either the pin channels are incorrect (possible or unlikely) or the trigger/disconnector is not aligning correctly.
Spikes probably did not send out your receiver with incorrect channels. Possible, but very unlikely.

Which leaves us with the trigger assy. Like Dano said, check that the pistol grip bolt does not protrude too far.  If it is too long it will push/pivot the trigger/disconnector assy so the disconnector rotates into the way.  Not all pistol grip bolts are correct.  If it is a problem you can grind or file it down to not protrude, or buy another one at home despot.

If that doesn't work then you are doomed.   OK, not doomed, but screwed, seriously screwed.  OK maybe not screwed, you will still have a life, but inconvenienced.  8^)

Possibly try going to your OH hometown and finding someone close to take a look. A second set of eyes helps.
It would also be really helpful to see if another fire group works.  

I bet on the pistol grip bolt/screw.  Can you remove the fire assy and take a picture of the firegroup housing to see how the pistol grip bolt/screw extends into the housing?

Let us know how this ends.

I could be a100% off but have you tried using a stock safery, I notice yours isn't.
Tolerance stacking is my guess
Edit just removing the safety and trying it will tell you if it's causing any issues.

Good thought.

Me no like tolerance stacking.

Thanks for the replies folks. Unfortunately, removing the safety does not change anything, same problem. And I have tried this without the grip installed, and visual inspection shows that the grip screw is nowhere near the inside of the receiver.

Was worth a try and didn't cost anything.

In my lower, the hole for the grip screw does not extend into the pocket.  I measured the pin holes. They are separated .31 in, vertically and .82 in. horizontally.  My blue print shows those dimensions as .314 and .843, respectively.  I can only measure within about .02, but I think it's safe to say that they are too close together, even though the KNS pins fit.  I tried an alternate disconnector and it was worse.  The ALG disconnect interferes by about .02, and the spare by about .10.  If I get the free time I will stone back the nose of the spare disconnect to see if I can get a functional FCG.  However I would prefer use the ALG disconnect, and not alter it if possible.  What could I try, other than a new receiver?

OP, have you measured your receiver? Have you tested the trigger group in another receiver?

OK, to sum up.
We've heard from Commando that his handle screw is fine, but not from Ike.  And I think Dano knows what he is talking about wrt the handle screw indicating a problem with the selector well in advance of interfering with fire control group geometry, so Ike's problem is probably not handle screw either.

So, does that leave receiver problems in both cases?  Hard to believe.

Ike,  IM me your address and I will send you a mil spec FCG to try.  I know it works properly, so if it doesn't work for you then you have a receiver problem.
You could also send the receiver and ALG to Spikes and let them figure it out.  

Rick: Done. Very generous of you to help me out, I appreciate it!

Commando: no,I have not measured the holes yet. Unfortunately I don't have any calipers that could be precise enough. But just to clarify, it is not the grip screw that is the problem. I have triple checked that, no issues, not even close to protruding.

Any news?

Well, I was able to shorten a disconnector and I now have normal trigger function,  This ALG trigger is fantastic.  I can't perceive any creep or take up,  the break is a smooth, short crack, and it has a solid, positive reset.  I've never shot a stock AR trigger, but I've shot handguns with bad triggers (cough LC9 cough) and this is the best trigger I have used on a gun under $1500. I hope the OP gets his functional.

Sorry it took so long to get back to everyone. Rick, I tried the trigger you sent, the issue was the same. However,  after some light filing on the disconnect,  I have had normal function checks all night. I plan to test fire it Thursday and I will post a range report on it then. So far though it seems to be functioning normally. Thank you all so much for the help and Rick, thank you for the trigger to work on. It was a huge help! Also I can echo what the other user posted, the ALG trigger is great. Stiff, but very crisp and clean break. Absolutely no creep.

Good to hear you are up and running!  It sounds like those particular receivers have trigger pin drillings and hammer pin drillings that are just enough "special" to require some hand fitting of the FCG.
Good shooting to you!