80% P320 Compatible Insert - MUP 1



80% P320 Compatible Insert - MUP 1




Building a firearm in your garage is easy with help from JSD Supply. We offer a diverse inventory of parts, like 80% lower inserts, that make a great base for a variety of handgun projects.

The Modular Universal Pistol 1, or MUP 1, is compatible with current P320 upgraded parts, including SIG’s line of “drop safe” firearms. You can use this insert to make a 9mm, 40 S&W, 357 SIG, and 45acp (with slight modifications). That means this SIG P320 insert is extremely versatile. Design a SIG P250, a P320, or even put it in the EXO-1 Chassis system.

This quality insert is made from type 316 stainless steel, so it will last you through years of use.

Roughly 2 weeks for shipping

Easy to Build Firearms

Since 2013, we’ve been the ultimate DIY firearm solution. With this insert, you have a base from which to build your new favorite firearm in the privacy of your own garage. To finish the insert, you need the following:

  • All Holes
  • Bend Slide Rails
  • Trim Rails to Size

You can easily complete all of the operations on your SIG P320 insert with a Dremel, Drill Press and our MUP-1 Jig (sold separately). Follow instructions to complete a gun that looks, feels, and operates just like one from the manufacturer but without the hassle of paperwork.

The Hassle-free Way to Get a Handgun

Whether you need an 80% lower insert or something else for your firearm project, rely on JSD Supply. Our team has tested everything we sell and are happy to make recommendations so you can complete your build. Offering straightforward services and fast shipping, we are the hassle-free way to get a handgun without background checks or concerns about serial numbers.

5 reviews for 80% P320 Compatible Insert – MUP 1

  1. ROBERT B (verified owner)

    Surprisingly simple. Was hesitant because I have no machining experience. This plus the finishing jig and video (and patience) made a success!

  2. tim (verified owner)

    Fast shipping insert looks great will buy more very soon!

  3. Steven Speidel (verified owner)

    A+++++ Excellent craftsmanship! Very helpful customer service and fast shipping! JSD answered a question I had within minutes . Thank You!!

  4. [email protected] (verified owner)

    Fits good , easy to work .
    Either it or jig need markings for manual safety cutout .

  5. [email protected] (verified owner)

    Fits good , easy to work .
    Either it or jig need markings for manual safety cutout .

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