How to Install an AR-15 Pivot Pin

Larry Potterfield • August 28, 2023

Installing the pivot pin on an AR-15 is a simple process on this rifle. Some Colt receivers, however, use a screw rather than a detent to secure this pin. Start the assembly by lubricating the pivot pin with oil,

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Oil pivot pin

and apply some grease to the spring and detent.

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Grease detent and spring

This job is almost impossible without a pivot pin installation tool like this one by Model 1.

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Pivot pin installation tool

To use, simply insert the tool through the pivot pin bosses on the front of the lower, and line up the hole in the tool with the detent hole in the lower.

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Align the holes

Now insert the spring,

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Insert detent spring

then the detent.

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Insert detent

Depress the detent with a small punch until the detent is just completely inside the detent hole.

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Push detent in with punch

Then rotate the tool carefully to capture the detent with the tool.

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Rotate installation tool

The detent rides in this groove in the pivot pin.

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Detent rides groove

Insert the pivot pin, pushing the installation tool out as you go.

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Replace tool with pin

Now you can rotate the pivot pin until the detent snaps into the groove.

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Rotate pivot pin

The pin is now properly installed and captured by the detent.

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Detent snaps into groove

--Larry Potterfield