ar trigger problem...

[mnichols]

First off... im using a poly80 polymer 80% lower. and yes i do realize that this is the root of my problem. im not ready to give up on it yet, im hoping there is a fix, i just need some help figuring out what to do next.

so, i got everything milled out, drilled my holes using the indicators on the lower. i got my magazine release and bolt catch in fine.

Trigger, disconnect and hammer all went in, but when i manually cock the hammer back and pull the trigger, it wont release.

If i press down on the back of the disconnect, it releases the hammer, and i can then pull the trigger and the hammer falls just fine.

It looks to me as though the disconnet wont release the hammer. so i thought maybe my hammer pin or trigger pin holes were in the wrong place, but my calipers tell me they have the right spacing.

Any advise would be greatly appreciated.

Thanks

[TacticalPlinker]

Did you install the disconnector spring? Do you have the trigger & hammer springs installed correctly?

[shooterfpga]

Look at your disconnector spring and make sure it is the right one. There are two springs that look alike but one is incorrect for the disconnector.

[mnichols]

Disconnect spring is installed fat end down.

[mnichols]

And yes hammer and trigger springs are good. i watched a few youtube videos just to make sure.

[unobvs]

Try this

Is the safety selector in yet? IF not, install it and try again.

[mnichols]

Safety selector was not in. i cant get it in while the trigger pin is in, as the back of the trigger is in the way.

If i take the hammer out and slide the trigger pin out, i can get the safety selector in.

But, the disconnect still hang up as before. and now after i manually press the back of the disconnect, the trigger will no longer release the hammer.

Perhaps the selector hole is too low? I think this is an additional problem, not the cause of my original issue. All the videos i have watched show that the trigger/hammmer should function before the safety is installed.

Please correct me if im wrong.

And thank you to those who have responded.

Any other ideas?

One spec i cant seem to find on any blueprints is th distance from the top of the reciever down to the pin holes and selector holes. i only see the elevation differences between the holes.

[Diesel12]

I was having similar issues with my EP poly lower build. They say to cock the hammer back to lower the rear of the trigger so that you can insert the safety selector. I tried that, but the rear of the trigger would not allow me to insert the safety selector. It was still above the safety selector hole. I ended up resolving the issue by grinding down the rear top area of the trigger so that it would clear the safety selector. Make sure you know what you are confident with your skills before attempting this. Seems to work good now.
I think that's an issue with the poly lower receivers since there is no jig involved. Drilling the safety, trigger, and hammer holes are pretty important.

[inbox485]

If you measured the trigger and hammer pin locations, it is either the floor isn't deep enough, or the lower parts kit is defective. Since the selector can't fit in, I'm betting you need to measure how much the rear of the trigger sticks up through the selector hole from the side, and take that much off the floor. Then the trigger well be able to Rock back enough to let the selector in and release the trigger going the other way. Just make sure that the distance you need to take out leaves some floor material. That jig fits tight enough I doubt holes being off is the issue.

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[mnichols]

This makes sense. i have sone room to go a bit deeper, but not enough to clear the safety.

is there any real downside to shaving a little off the underside of the back of the trigger after ive gone as deep as i can into the floor?

[mnichols]

Now that i think about it, that would only solve my safety problem, and not my trigger/disconnect problem...

Ill go into the floor as much as i can and see what that gets me.

Thanks

[bauern]

Safety selector was not in. i cant get it in while the trigger pin is in, as the back of the trigger is in the way.

If i take the hammer out and slide the trigger pin out, i can get the safety selector in.

But, the disconnect still hang up as before. and now after i manually press the back of the disconnect, the trigger will no longer release the hammer.

Perhaps the selector hole is too low? I think this is an additional problem, not the cause of my original issue. All the videos i have watched show that the trigger/hammmer should function before the safety is installed.

Please correct me if im wrong.

And thank you to those who have responded.

Any other ideas?

One spec i cant seem to find on any blueprints is th distance from the top of the reciever down to the pin holes and selector holes. i only see the elevation differences between the holes.

The distance from the top are as follows:

Hammer pin: 0.625"
Trigger pin: 0.939"
Selector: 0.714"

The take down pins are 0.250" from top. If your finger is off the trigger, the hammer should not catch the disconnector as the trigger will spring forward slightly (disconnector moves back) as the hammer is pulled back past the "sear" edge of the trigger. This is before the disconnector can catch the hammer. If it's catching the hammer then the hammer/trigger are too close together or the LPK parts are out of spec. You can try to stone,file,grind the surface of the disconnector to clear the hammer depending on your comfort level. The gap between the the hammer and disconnector is very very small.

[inbox485]

This makes sense. i have sone room to go a bit deeper, but not enough to clear the safety.

is there any real downside to shaving a little off the underside of the back of the trigger after ive gone as deep as i can into the floor?

Kinda sorta. Good parts would be surface hardened, but that isn't a high wear area. I'd be fine doing that to get it working. I'm finding it a bit odd though that you confirmed the hole locations with calipers, but you don't have enough floor to get the selector in. You might want to make a buddy that knows or at least has a good in spec complete AR for you to compare to. There is a ton online, but it is hard to get in context without something to hold in your hand and look at.

[6mmintl]

Does the disconnector release the hammer when you release pressure on the trigger? if not you may have trigger spring installed incorrectly.

[mnichols]

Thanks for all the responses. you guys have been a big help. im going to mill the floor out as much as i can and try again.

My brother has a spec aluminum lower, it will just be a whils before he can bring it over.

thanks again