Step L2: Magazine Catch Installation
Objective: In Step L2 of lower receiver assembly, we will install the magazine catch assembly onto the lower receiver.
NOTE: This step is not applicable if building an AR-9 on the Aero Precision EPC platform, which comes with a proprietary magazine catch and button installed from the factory.
Tools Required
1: A mag well vice block is a good way to secure your lower during the installation of small parts.
2: The tool that we use is no longer available from the manufacturer (Mercy Firearms Magazine Button Assist Gadget). We have reached out to them to find out why and got a message that they are no longer in business. For now, we have found some 3D printer files for extended magazine release buttons that can be used to print a similar device. In lieu of a dedicated device, a 1/4″ piece of wooden dowel or a non-marring (i.e. plastic) punch can also be used.
Components Required
| Quantity | Component |
|---|---|
| 1 | Lower Receiver |
| 1 | Magazine Catch |
| 1 | Magazine Catch Spring |
| 1 | Magazine Release Button |
| 1 | Magazine |
Instructions
Secure the Lower
If using a mag well vice block, install a mag well vice block into your vice and install your lower receiver onto it.
Step L2.0: Remove Existing Magazine Catch (replacement/upgrade only)
If you are replacing your existing magazine catch or release button (or need to remove the magazine catch assembly for any other reason), first ensure the firearm is unloaded.
Depress the magazine release button fully. You will likely need a non-marring object (mag release button tool, plastic punch, or 1/4″ wooden dowel) to fully depress the magazine release button into the lower receiver. You may also need to remove the bolt catch, if the magazine catch will not clear it.
With the magazine release button fully depressed, rotate the magazine catch counterclockwise (as viewed from the left side of the receiver) until the threads are no longer engaged with the magazine release button.
Remove the magazine release button, magazine catch, and magazine catch spring from the lower receiver.
Step L2.1: Lubricate the Magazine Catch Shaft
Wipe a thin coat of wet lubricant on the round shaft of the magazine catch.
Step L2.2: Insert the Magazine Catch
Feed the magazine catch shaft through the hole in the left side of the lower receiver.
Step L2.3: Add the Magazine Catch Spring
From the right side of the lower receiver, feed the magazine catch spring onto the magazine catch shaft.Â
Step L2.4: Add the Magazine Release Button
If you are installing an extended, paddle-style magazine release button, remove the paddle from the button per the manufacturer’s instructions.
Place the magazine release button in the hole in the right side of the lower receiver. This will push the magazine catch out the right side of the lower receiver slightly.
Step L2.5: Thread the Magazine Catch
While depressing the magazine release button from the right side and pressing the magazine catch from the left, rotate the magazine catch clockwise (as viewed from the left side of the receiver). This will engage the threads into the magazine release button. Use caution to not cross-thread the magazine catch and magazine release button. Continue to rotate the magazine catch until you cannot rotate it without contacting the lower receiver.
Using a magazine button tool or non-marring punch, push the magazine release button into the lower receiver and continue to rotate the magazine release.
- If you are using a standard magazine release button, continue to rotate the magazine catch until the threaded shaft of the magazine catch is flush (or just short of flush) with the surface of the magazine release button.
- If you are using the Odin Works XMR3, we find that 7-8 rotations (once the threads engage) is perfect.
Step L2.6: Verify the Magazine Engagement and Release
If you are using a paddle-style magazine release button, you should perform this testing with the paddle installed.
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Using an empty magazine, insert the magazine into the mag well of the lower receiver. The magazine catch should engage and lock the magazine in place. If it does not, remove the magazine and rotate the magazine catch (per Step L2.5) one turn clockwise (as viewed from left side of receiver). Repeat the verification.
Depress the magazine release button. The magazine should fall free. If it does not, remove the magazine and rotate the magazine catch (per Step L2.5) one turn counterclockwise (as viewed from left side of receiver). Repeat the verification.
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