Hammer hook hits sear as hammer is manually cocked

[uranus]

Hi:

I recently purchased a PWA lower with internals. When I manually cocked the hammer, the hammer hook appeared to hit the sear. I removed the trigger and hammer (don't know what manufacturer) and installed the trigger and hammer from another lower (DPMS or CMT; can't remember). I have four other AR's but have never experienced this problem.

Additionally, when I installed a set of KMS Gen II anti-rotational pins, the connecting bars would not seat properly without hitting the mag fence. In other words, the distance between the trigger pin and the mag fence is too short. I have also encountered this on a new LMT lower but did not have the problem with the hammer hook hitting the sear as the hammer was manually cocked.

I suspect that the holes for the trigger pin were drilled too far forward.

Other than to return the receiver, any suggestions?

Thx,

uranus

[AR15barrels]

The AR-15 does not have a dedicated piece known as a sear.
Both the hamer and trigger have engagement surfaces, but no seperate sear.
Perhaps you mean the disconnector?

Here is a good picture to show proper nomenclature:

[uranus]

Randall:

The front of the trigger where it engages the notch in the lower portion of the hammer. The part of the trigger which lowers when the trigger is pulled, releasing the hammer.

[AR15barrels]

Randall:

The front of the trigger where it engages the notch in the lower portion of the hammer. The part of the trigger which lowers when the trigger is pulled, releasing the hammer.

Those indeed are the two engagement surfaces.
It's normal for the front of the trigger to pop up (and the trigger shoe to move forward) if you were not holding the trigger to the rear while you manually cock the hammer.
This is the trigger re-setting to be able to hold the hammer on the cocking notch.

Without the trigger being held to the rear, it's normal for the trigger to ride against the hammer as you cock it because the trigger is spring loaded into engagement with the hammer.

When you are shooting the gun and pull the trigger, the carrier cocks the hammer, but the disconnector holds the hammer until you release the trigger.

I'm not sure that you actually have a problem.
At least I can't understand your description of it if you do.

[uranus]

Randall:

Thank you for your explanation.

When I held the trigger to the rear and manually cocked the hammer (after I read your reply), the hammer moved smoothly and without resistance, and the hammer notch did not appear to hit the front of the trigger.

I think that it will function correctly. I'll put an upper on it later this week and test it.

Thx,

uranus