Lower Receiver Assembly (AR-9, AR-15, and AR-10/LR108)
Step L7: Pistol Grip Installation
Objective: In Step L7 of lower receiver assembly, we will install the pistol grip onto the lower receiver.
Tools Required
1: Some pistol grips include a flat head pan-head screw. Others include a 3/16″ hex bolt. Refer to the table below or the grip manufacturer’s instructions when determining the required tool.
| Grip/Grip Screw/Bolt | Screw/Bolt Style |
|---|---|
| Magpul Grips (All) | Flat Head |
| ERGO Grips (All) | 3/16″ Hex Key |
| Luth-AR LR-23 Grip Bolt | Flat Head |
Components Required
| Quantity | Component |
|---|---|
| 1 | Lower Receiver |
| 1 | Pistol Grip |
| 1 | Pistol Grip Screw/Bolt |
| 1 | Pistol Grip Lock Washer (as applicable) |
Instructions:
NOTE: If you are building an AR-10 on the Aero Precision M5 platform, you will need to install the takedown pin assembly (per Step L8) before you install the pistol grip, as the detent cavity is oriented from the bottom instead of from the rear.
Step L7.0: Remove Existing Pistol Grip (replacement/upgrade only)
If you are replacing your existing pistol grip (or need to remove the pistol grip for any other reason), first ensure the firearm is unloaded.
Insert the appropriate driver (flat head screwdriver or 3/16″ hex driver) into the pistol grip and loosen the pistol grip screw/bolt. Remove the pistol grip screw/bolt and lock washer, if equipped.
Invert the firearm and carefully remove the pistol grip. The safety selector spring and detent (and takedown pin spring and detent for M5 builds) will be held in place by the pistol grip.
Step L7.1: Place Pistol Grip
With the lower receiver still inverted from the previous step and while ensuring the correct orientation of the safety selector, carefully feed the pistol grip onto the lower receiver. Be sure to feed in line with the safety selector spring, which will protrude from the bottom of the lower receiver, to avoid kinking it. Depress the safety selector spring into the lower receiver with the pistol grip. Maintain light pressure on the pistol grip as you proceed to the next step.
Step L7.2: Assemble the Lock Washer onto the Bolt (as applicable)
Thread the pistol grip lock washer onto the pistol grip screw/bolt, as applicable.
Step L7.3: Install the Pistol Grip Bolt and Lock Washer
WARNING: DO NOT USE THREAD LOCKER. Some grip screws/bolts will have an elastomeric compound applied to the threads; this is not the same as your typical thread locker.
Using a 3/16” hex wrench or flat head screwdriver, carefully feed the pistol grip screw/bolt and pistol grip lock washer through the pistol grip. Once the tip of the pistol grip screw/bolt contacts the lower receiver, carefully rotate it counterclockwise until you feel a click of the threads. At this point, carefully begin to rotate clockwise to engage the threads of the lower receiver. This technique should avoid cross threading.
Hand tighten the pistol grip screw/bolt.
Step L7.4: Verify Safety Selector Function
Before you proceed, verify that the safety selector switch functions properly. If not, remove the pistol grip and verify that all components are installed properly.
Step L7.5: Torque the Pistol Grip Bolt (optional for hex bolts only)
Follow your grip manufacturer’s instructions for torquing (most grips do not need to be torqued). If torquing is recommended by the manufacturer, set your torque driver to the recommended torque setting. Install a long bit onto the driver. Tighten the pistol grip bolt until the torque driver slips.
If you are building an AR-15 or AR-9, proceed to Step L8 (installation of the takedown pin).
If you are building an AR-10, proceed to Step L9 (installation of the receiver extension).