First, this isn't a complaint. I swapped my FCU from a full size frame to a compact, as I've done several times before. It slid in place like it always does. The slide slid on like it always does. I dry fired the pistol and got a click and then the trigger was dead. No reset. No clicks. Running the slide wouldn't reset the trigger. I stripped the gun again, reassembled it again, and it seems to be working normally again. What the heck did I do so I can avoid doing it again?

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More info than what you asked for, but in case you are curious...

When the Trigger is pressed to the rear, the Trigger Bar is pulled forward.

As the Trigger Bar moves forward, the rear arm makes contact with the Safety Lever and rotates it upwards.

The upper movement of the Safety Lever presses the Safety Lock up so it is no longer blocking the Striker from moving forward.

It is the tension of the Trigger Bar Spring that returns the Trigger Bar and Trigger to the resting position after firing. The tension of the Safety Lock Spring and the Safety Lever Spring return these components to their resting positions after firing.

Had functionally not returned after the removal & reassembly of the FCU, I would bet you a dollar that the Trigger Bar Spring was broken.

Since it is functioning correctly, I expect the Trigger Bar Spring was hung up and unable to return the Trigger Bar to testing position.

This message has been edited. Last edited by: sleepla8er,

To fix the problem after you reassemble the gun, always pick up the slide release a few times and work it.
This unlocks the built in safety mechanism.
You also cant insert a magazine while the gun is in this safety mode.

quote:

Originally posted by Rockyriver:
To fix the problem after you reassemble the gun, always pick up the slide release a few times and work it.
This unlocks the built in safety mechanism.
You also cant insert a magazine while the gun is in this safety mode.

Yep, during reassembly always lock the slide to the rear and then turn the take down lever into the locked position. If your take down lever flips into place on its own when pulling the slide to the rear still lock it to the rear and cycle the take down lever just to be safe. And always function check after reassembly.