How To Remove And Install A Sig Sauer P320 FCU

The Sig Sauer P320 stands out in the world of firearms for its adaptability and precision engineering. Central to its innovative design is the Fire Control Unit (FCU), the heart of this modular handgun. Understanding how to safely remove and reinstall the FCU is essential for customizations, maintenance, or troubleshooting. This guide is tailored for both seasoned enthusiasts and new owners of the P320, offering a clear, step-by-step walkthrough of the FCU removal and installation process.

In this guide we will be using our Wilson Combat WCP320 Compact to show the process. If interested in our In-Depth Review of the Wilson Combat WCP320 Compact Click Here.

What You’ll Need

To remove and install the Fire Control Unit (FCU) in your Sig Sauer P320, the process is surprisingly straightforward and requires no special tools. Here’s what you’ll need:

1. Your Hands: That’s right, the simplicity of the P320’s design means that removing and reinstalling the FCU can be done entirely by hand, without the need for any additional tools.
2. Flat Head Screwdriver: Only needed to aid in removing the fcu from grip module if its being stubborn. But is not needed!

Safety Precautions

Before you begin the process of removing or installing the Fire Control Unit (FCU) in your Sig Sauer P320, it’s crucial to observe the following safety precautions:

1. Ensure the Firearm is Unloaded: Always check that the firearm is completely unloaded. Remove the magazine and check the chamber to ensure there are no rounds present.
2. Work in a Safe Environment: Choose a well-lit, distraction-free area to work on your firearm. This reduces the risk of accidents.
3. Point the Firearm in a Safe Direction: Even when you have verified that the firearm is unloaded, always point it in a safe direction as a habitual safety practice.
4. Avoid Trigger Engagement: During the process, be mindful not to inadvertently engage the trigger unless specifically required during the function check.
5. Wear Eye Protection: Small components under tension could potentially fly out. Wearing eye protection is a simple step to safeguard your eyes.
6. Keep the Work Area Organized: An organized workspace helps prevent loss of small parts and keeps everything within easy reach.

Remember, safety should always be a top priority when handling firearms. Taking these precautions ensures not only your safety but also to others around.

Removing the FCU

Removing the Fire Control Unit (FCU) from your Sig Sauer P320 is a straightforward process that can be done safely and efficiently by following these steps:

Clearing the Firearm

Begin by removing the magazine from your P320.

Lock the slide in its rearmost position. This can be done by pulling the slide back fully and engaging the slide catch lever to lock the slide.

Visually inspect the chamber to verify that it is clear and empty, ensuring the firearm is unloaded.

Removing the Slide

With the slide locked back, rotate the takedown lever (located on the frame) clockwise until it stops.

Carefully, release the slide catch lever, allowing the slide to move forward. Then slide the slide off the front of the frame and set it aside.

Removing the Takedown Lever

Rotate the takedown lever counter-clockwise. While rotating, pull the lever out from the frame.

Remove the Fire Control Unit

With the takedown lever removed, the FCU is now ready to be taken out. Firmly grasp the front part of the FCU and gently lift it out of the grip module. If the FCU is being stubborn and doesn’t want to lift out with your fingers you can use a flat head to help start lifting it out.

At this point your FCU can be swapped into a new grip module or perform a deep cleaning on your firearm. Click here to see our step by step guide on field stripping, cleaning and lubricating a Sig P320.

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Installing the FCU

After swapping your Fire Control Unit (FCU) to a new grip module or performing a deep cleaning, the reassembly of your Sig Sauer P320 is pretty much the reversal of the removal process.

Install the FCU into the Grip Module

Align the rear of the FCU with the rear of the grip module.

Slightly depress the trigger while sliding the front part of the FCU into place. Guiding the trigger into the grip module trigger slot.

Once the FCU is in the grip module, pull the trigger to fully seat the FCU backward into place.

Install the Takedown Lever

Position the takedown lever at about a 7 o’clock direction, aligning it with the tab inside the grip module.

Apply pressure and turn the lever counter-clockwise until it is completely seated and flush with the opposite side of the grip module. Rotate the takedown lever clockwise to prepare for installation of the slide.

Remate the Frame with the Slide

Align the frame with the guide rails on the slide.

Slide the frame rearward, locking it in its rearmost position.

Rotate the takedown lever counter-clockwise to its resting position.

Release the slide catch lever, allowing the slide to move forward into place.

At this point, your Sig Sauer P320 is fully reassembled. It is now ready for a functions check to ensure that all components are properly installed and the firearm is operating correctly.

Functions Check

Once you’ve reassembled your Sig Sauer P320, it’s crucial to perform a function check. This ensures the firearm operates correctly and safely after the Fire Control Unit (FCU) removal and installation process.

Ensure the Firearm is Unloaded and Cleared

• Always start by verifying the firearm is completely unloaded. Remove the magazine and visually check the chamber to ensure there are no rounds present.

Check Slide Operation

• Pull the slide to the rear and release it, allowing it to return to the forward position. Ensure it moves smoothly without any obstructions.

Inspect Slide Lock with Empty Magazine

• Insert an empty magazine into the pistol.
• Pull the slide back and ensure it locks open, indicating the slide catch lever is functioning as expected.
• Release the slide catch lever and allow the slide to return to the forward position.

Check Magazine Release

• With the magazine inserted, press the magazine release to ensure it ejects smoothly.
• Re-insert the magazine and verify that it locks into place securely.

Perform a Dry Fire Test

• Point the firearm in a safe direction and, if possible, use a snap cap or dummy round. Press the trigger to simulate firing to ensure all mechanisms are working correctly.

Warning: If any part of this function check fails or if you notice any unusual resistance or sounds during the check, stop using the firearm immediately and consult with a professional gunsmith or SIG SAUER for further inspection and advice.

This function check is a vital part of ensuring the safety and reliability of your Sig Sauer P320. Always prioritize thorough inspection and verification after reassembly.

Final Thoughts

Successfully removing and reinstalling the Fire Control Unit (FCU) in your Sig Sauer P320 is a key skill for any P320 owner. This guide aimed to provide you with clear, step-by-step instructions to ensure you can perform these tasks with confidence and safety.

Remember, familiarity with your firearm not only enhances your ability to customize and maintain it but also deepens your understanding of its operation, contributing to responsible gun ownership. Regular maintenance, including FCU removal and installation, is essential for the longevity and reliability of your Sig Sauer P320.

FAQs on Removing and Installing the Sig Sauer P320 Fire Control Unit

1. Is it difficult to remove the FCU from the Sig Sauer P320?
   • No, removing the FCU from the P320 is relatively straightforward. The process can be done by hand without the need for specialized tools.
2. Do I need any special tools to remove or install the FCU?
   • No special tools are required. The removal and installation of the FCU can be performed with just your hands.
3. How often should I remove the FCU for cleaning?
   • It’s recommended to remove and clean the FCU as part of your regular cleaning routine, especially after extensive use or exposure to harsh environments.
4. Can switching the FCU to another grip module affect the performance of my P320?
   • As long as the grip module is compatible with your P320 model and the FCU is installed correctly, there should be no negative impact on performance.
5. What should I check during the function verification after reassembling the P320?
   • Ensure that the slide operates smoothly, the trigger mechanism functions properly, and all features, like the slide catch lever, are operating correctly.
6. Is it safe to interchange FCUs between different P320 models?
   • The FCU is designed to be interchangeable within P320 models. However, always verify compatibility and conduct a function check after any such interchange.
7. What are the risks of improperly installing the FCU?
   • Incorrect installation can lead to malfunctions, reduced performance, and potentially unsafe conditions. Always follow guidelines closely and perform a function check after reassembly.

By understanding these aspects of FCU maintenance, you can ensure your Sig Sauer P320 remains a reliable and safe tool in your collection.

If you missed our last post Click Here to see our Step by Step guide on How To Fieldstrip, Clean and Lubricate a Sig Sauer P320