Upper Receiver Assembly (AR-9, AR-15, and AR-10/LR108)
Step U8: BCG and Charging Handle Installation
Objective: In Step U8 of upper receiver assembly, we will install the bolt carrier group and charging handle.
Tools Required
Components Required
| Quantity | Component |
|---|---|
| 1 | Upper Receiver |
| 1 | Bolt Carrier Group |
| 1 | Charging Handle |
Instructions:
Step U8.0: Remove Existing Charging Handle/BCG (replacement/upgrade only)
If you are replacing your charging handle or BCG (or need to remove them for any other reason), first ensure the firearm is unloaded.
With the upper receiver open (secured to lower receiver by pivot pin) or removed from the lower receiver, and inverted, retract the charging handle. Lift the BCG out of the upper receiver/charging handle. Lift the charging handle out of the upper receiver (the alignment tab will pass through the applicable cuts in the upper receiver).
Clean the inside of the upper receiver and any parts that will be reused.
Step U8.1: Lubricate the Upper Receiver, Charging Handle, and BCG
This is where the most movement and metal-on-metal action happens. Don’t be afraid of lubricating these parts.
Using a clean wipe, apply a coat of wet lube to the inside of the upper receiver, the exterior of the BCG (avoid the mouth of the gas key), and the charging handle.
Apply a drop of wet lube to all of the key points on the BCG using a dropper. Refer to Lubricate for lubrication points and instructions.
Step U8.2: Insert the Charging Handle
Insert the charging handle into the upper receiver. The alignment tab on the charging handle will slide into the applicable cutout in the upper receiver. Do not latch the charging handle to the upper receiver yet.
Step U8.3: Insert the BCG
With the cam pin to the front of the BCG (in line with the gas key), seat the gas key into the charging handle and insert the whole assembly into the upper receiver. Push forward on the BCG until the charging handle latches the upper receiver.
Troubleshoot
If the BCG will not seat completely into the upper receiver, STOP. There may be an issue with the lugs on the bolt and/or barrel extension. Visit Troubleshoot for diagnosis.