P80 and SIG P320 Builds: A Step-by-Step Guide for Beginners

If you’re looking to build a Sig P320 this is the guide for you.

Building your own custom firearm from a P80 or SIG P320 frame is an exciting and rewarding project, allowing you to create a gun tailored to your exact preferences and needs. With many customizable options, from grip styles to trigger systems, these builds are ideal for both beginners and seasoned gun enthusiasts. At Route 66 Guns & Ammo, conveniently located halfway between Las Vegas and Los Angeles, we proudly serve Barstow, Hesperia, Apple Valley, Phelan, and Victorville, offering guidance to help you complete a successful build. While these frames are no longer legal in California, we wanted to write this article to help anyone else that may be looking to upgrade their P320.

In this guide, we’ll walk you through the step-by-step process of building a custom firearm using P80 and SIG P320 frames, including essential tools, tips, and legal considerations to keep in mind.

Why Choose P80 and SIG P320 Frames for Custom Builds?

P80 (Polymer 80) and SIG P320 frames are popular options for firearm builds due to their customizable features and ergonomic designs. Both frames allow you to create a handgun that feels unique to your preferences and shooting style.

        •        Polymer 80 Frames: Known for their durability and grip enhancements, P80 frames are compatible with many Glock components, making them a top choice for custom Glock-style handguns.

        •        SIG P320 Frames: SIG P320 frames, especially the PF320PTEX, offer a similar level of customization with a modular design that supports a wide range of parts and accessories.

Building your own handgun from these frames offers benefits such as improved ergonomics, compatibility with aftermarket parts, and the satisfaction of assembling a firearm from scratch.

Step 1: Choose Your Frame

The first step in your custom build is selecting the right frame. For beginners, it’s essential to pick a frame compatible with the type of parts you want to use and one that aligns with your intended purpose, such as self-defense, range shooting, or competition.

P80 Frames for Glock Builds

        •        PF940V2: Full-size frame compatible with Glock 17 components. Ideal for users who prefer a full-size handgun.

        •        PF940C: Compact frame compatible with Glock 19 components. Perfect for a concealed carry build.

        •        PF940SC: Subcompact frame compatible with Glock 26 components, offering a more compact and portable firearm.

SIG P320 Frames

        •        PF320PTEX: Designed for the SIG P320, this frame offers an ergonomic grip and is compatible with a variety of P320 components, making it an excellent choice for SIG enthusiasts.

At Route 66 Guns & Ammo, we carry a range of frames to suit different preferences and uses, while we don’t carry and 80% frames we do have full frames and can special order you anything you may want. Our knowledgeable team can help you select the frame that best matches your goals and experience level.

Step 2: Gather Your Tools and Parts

Once you’ve selected your frame, it’s time to gather the necessary tools and components to complete your build. Here’s a list of essentials:

Tools

        •        Jig Kit: P80 frames require a jig for precise milling and drilling. A jig kit acts as a guide, helping you make accurate cuts and drill points.

        •        Drill Press or Hand Drill: A drill press is ideal for precision, but a hand drill will also work for beginners.

        •        End Mill Bits and Drill Bits: These bits are used to mill out the necessary sections of the frame.

        •        Clamps: Used to secure the frame while milling and drilling.

        •        Screwdrivers and Punches: Required for assembling parts like the trigger, slide, and pins.

Parts

        •        Slide: Choose a slide compatible with your frame (e.g., Glock 17 or Glock 19 slides for P80 builds).

        •        Barrel: Select a high-quality barrel for reliability and accuracy. Match the barrel size to the slide and frame.

        •        Trigger Kit: A quality trigger kit can improve the feel and response of your firearm.

        •        Lower Parts Kit: Includes components such as the slide stop, trigger bar, and pins needed to complete the lower assembly.

        •        Upper Parts Kit: Contains parts like the firing pin, extractor, and recoil spring for the slide assembly.

Step 3: Milling and Drilling the Frame

For P80 frames, the milling and drilling process is a crucial step to make the frame functional. Follow these steps to ensure accuracy:

1. Set Up the Frame in the Jig

Place the frame securely in the jig, aligning it according to the jig’s instructions. Secure it with clamps to prevent movement during milling.

2. Drill the Pin Holes

Use the jig’s guide holes to drill the necessary pin holes. Take your time with this step to ensure precision.

3. Mill the Rails and Barrel Block

Using an end mill bit, mill out the designated areas for the rails and barrel block. Make shallow passes to maintain control and avoid mistakes.

4. Inspect the Frame

After milling and drilling, inspect the frame for accuracy. Smooth out any rough edges to ensure all parts fit together seamlessly.

Note: The SIG P320 frame typically does not require milling, as it is a modular design that allows for straightforward assembly. Simply follow the instructions provided with your frame and parts for the best results.

Step 4: Assemble the Lower Receiver

With the milling complete, you’re ready to assemble the lower receiver. This involves installing the trigger, magazine release, and other components from your lower parts kit.

        1.        Install the Trigger Assembly: Place the trigger in the designated slot and secure it with the provided pins.

        2.        Attach the Magazine Release: Insert the magazine release and spring according to the frame’s instructions.

        3.        Add the Slide Stop and Pins: Install the slide stop lever and any remaining pins required for the lower assembly.

Refer to the assembly guide that comes with your lower parts kit to ensure each component is installed correctly. The team at Route 66 Guns & Ammo is also available to answer any questions you may have about assembling the lower receiver.

Step 5: Assemble the Slide

Next, it’s time to assemble the slide using your upper parts kit.

        1.        Insert the Barrel and Recoil Spring: Place the barrel inside the slide, followed by the recoil spring assembly.

        2.        Install the Firing Pin: Insert the firing pin and extractor, making sure each piece is correctly aligned.

        3.        Attach the Slide to the Lower Frame: Once the slide assembly is complete, attach it to the lower frame by aligning the rails and carefully sliding it into place.

This step can be tricky, so take your time and ensure all parts are correctly seated.

Step 6: Perform a Function Check

After completing the assembly, it’s essential to conduct a function check to ensure everything is working properly.

        •        Dry-Fire the Trigger: Check that the trigger moves smoothly and resets correctly.

        •        Rack the Slide: Pull the slide back and release it to test the recoil spring and slide movement.

        •        Inspect Safety Features: If your firearm has a manual or trigger safety, make sure it functions as intended.

Performing a function check before using live ammunition ensures that your firearm is safe to use.

Step 7: Legal Considerations and Compliance

It’s important to stay informed about federal, state, and local regulations regarding custom-built firearms. In some states, such as California, you may need to apply for a serial number and register the completed firearm. Federal regulations also apply, particularly if you modify your firearm in a way that may classify it as a short-barreled rifle (SBR) or another restricted type.

If you’re located in Barstow, Hesperia, Apple Valley, Phelan, or Victorville, our staff at Route 66 Guns & Ammo can provide guidance on the latest California regulations to help you stay compliant.

Final Thoughts on P80 and SIG P320 Builds

Building a custom firearm from a P80 or SIG P320 frame offers an unparalleled level of control, customization, and personal satisfaction. With the right tools, parts, and guidance, even beginners can successfully assemble a reliable and unique handgun.

At Route 66 Guns & Ammo, we’re here to support your custom firearm journey every step of the way. From frames and to lower parts kits and slides, we carry everything you need to complete a high-quality build. Visit us today to explore our inventory, ask questions, and start building your custom SIG P320 that fits your style and shooting needs.