AR Lower question

[silverado31794]

I built a AR lower a few years ago an just now put a upper on it an shot it today for the first time. For some reason when I shoot it , it will cycle but the trigger doesn't reset. You can move the safety selector switch an then it will reset. Anyone know what could be going on with it?

 

[user 71]

Trigger and/or disconnector installed incorrectly - possibly?

Pics of the inside of the lower, focused on the trigger parts would help.

Also, I had this problem once but it was not due to incorrect installation. The hammer - specifically - the hook to interact with the disconnector was out of spec. I changed hammers and the problem disappeared. What brand is your lower parts kit?

 

[user 71]

Have you function checked the lower with no upper on it?

skip to 1:50 in the video for function check

skip to 2:15 - does your hammer release from the disconnector when the trigger is released?

 

[Lazarus]

Definitely function test it.

I'll say that the trigger group is the trickest part of a lower build. You have make sure you have the springs and pieces all lined up and sitting on the grooves of the pins correctly.

 

[silverado31794]

I'll get pics later but its a PSA kit.

 

[wildmantaz]

Make sure the hammer and trigger springs are installed correctly.

Also check the little spring that is in the trigger under the disconnect.
I had one that did something like your problem and it was that little spring.

 

[silverado31794]

Found the prob. Took my factory built AR apart and a spring is in wrong place on the one I built.

 

[silverado31794]

 

[user 71]

Glad you got it worked out. If the hammer slides into place easily - you're doing it wrong. You usually have to fight that SOB into position and push the pin through while fighting the tension of the spring the whole time. It's one of the many times that I wish I had three arms.

 

[Wallace's]

Glad you got it worked out. If the hammer slides into place easily - you're doing it wrong. You usually have to fight that SOB into position and push the pin through while fighting the tension of the spring the whole time. It's one of the many times that I wish I had three arms.

...or use a slave pin/punch and it goes in with no issue. I tap the pin once started with a jeweler a hammer (plastic face) and the pin goes right in once the hammer is lined up on the other side. If you use a receiver block, it makes it super super easy.