AR-15 Build Part 5

In B.O. Special, I introduced the newest addition to the gun cabinet and reviewed the rifle kit from Del-ton.
In Part 1, we talked about tools and preparation and installed the magazine catch.
In Part 2. we installed the trigger guard.
In Part 3, we installed the bolt catch.
In Part 4, we installed the pivot pin.

This time, we’re going to install the trigger assembly.

The first step is to place the trigger spring onto the trigger.

It’s kind of hard to describe in words. The trigger spring has two closed coils that go over the protruding part of the trigger pin/pivot point area.

Coming off the coils are a closed, squared off loop on one side and two open “legs” on the other side.

To install the spring, start from the bottom front of the trigger and put the spring onto the trigger with the coils up and to the rear, the closed loop end up and toward the front and the “legs” down and toward the front.

I found it easier to tilt the spring so that I could put the coil on one side over the pivot point protrusion first, then pry the spring farther open to pop the others coil onto the other side of the protrusion.

When it’s on correctly, the closed loop should rest against the underside of the front horizontal surface of the trigger and the “legs” should stick out forward and down.

Not a very eloquent explanation, but that’s the best I can do without knowing the technical terms for the various protrusions and elements of the trigger.

Next, the disconnector spring goes into a well in the top of the trigger.

The disconnector spring is slightly larger in diameter at one end than the other. The larger end goes into the well.

The spring should snap into place, which should prevent it from falling back out.

Then the disconnector is placed over the spring.

There is an open, squared off cutout in the rear of the disconnector that seats over the disconnector spring. The hole in the disconnector aligns with the trigger pin/pivot point on the trigger. When installed, the trigger pin holds both the trigger and disconnector in place.

Then, while holding the disconnector in place with your finger, the trigger/disconnector assembly is placed into the receiver from the top, the trigger should poke through the hole in the receiver into the trigger guard area.

I used a pin punch to hold the trigger and disconnector assembly in the receiver while installing the trigger pin.

You will have to press the trigger/disconnector down against the spring tension of the trigger spring to get the holes aligned.

Then insert the trigger pin and, in the process push the pin punch out.

There are two grooves in the trigger pin (which is, incidentally, identical to the hammer pin)…one in the center and one off to one side.

The center groove is used on the hammer pin but serves no obvious purpose on the trigger. The off-center groove is what holds the trigger pin in place. When the hammer is installed, one of the legs in the hammer spring will lock into this groove in the trigger pin, which locks it in place.

It doesn’t matter which way the trigger pin is installed, but (according to the arfcom instructions) it is common practice to install it with the off-center groove to the left.

You will probably have to jiggle the trigger and disconnector a little as the pin is going in to get all the holes aligned.

All done.

Next time we’ll install the hammer.

Next Post in the series


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