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Jig for 80% P320 Compatible Insert

Out of Stock

The P320 by Sig Sauer® has thus far been a great addition to our industry. It gave us the idea of having one pistol that can be adaptable to any carry situation. This was done by defining the insert or the "guts" of the P320 as the legal "firearm," so you can modify everything around it, thereby changing its carry size and profile. If you intend to build a new pistol with that same end-all/be-all feel to it, but you want to build it yourself and without that new pistol price, then you need to start with the piece the government considers the firearm.

Starting a P320 build? Read the Build Guide first!

Once you have the MUP-1, you'll need the jig that will allow you to finish the remaining work to be for for the insert to be functional. We're excited to bring you the necessary jig. The Jig for the P320-compatible MUP-1 will guide you and be your template for the rest of the work you need to do to complete the insert.

Steps Remaining

To finish the insert and make it ready for use, use this jig to complete the following steps:

  • Drill all holes
  • Bend side rails
  • Cut rails to size

For a great overview on these steps, check out JSD Supply's informational video here.

DISCLAIMER: “Sig Sauer” is a federally registered trademark of Sig Sauer, Inc. and is one of many trademarks owned by Sig Sauer, Inc. Neither Gun Builders Depot, a/k/a nor this site are affiliated in any manner with, or otherwise endorsed by, Sig Sauer, Inc. The use of “Sig Sauer” on this page is merely to advertise the sale of Sig Sauer pistols, parts, or components. For additional genuine Sig Sauer, Inc. products and parts visit

WARNING: Handling firearms parts and accessories can expose you to lead and other petroleum products known to the State of California to cause cancer and reproductive harm. For more information go to:

Shipping Restrictions

Shipping of various parts and/or accessories are prohibited to states and locales (ie New Jersey, California, New York, etc…) with restrictions against certain parts and/or accessories or "assault weapons" (i.e. states with high-capacity magazine restrictions, manufacturing of semi-automatic weapons, etc..). It is your responsibility to be aware of your local firearms laws before purchasing from our website or machining a firearm. We try our best to keep our shipping page current, but laws change daily. only ships within the United States. Federal legislation dictates we cannot ship our products internationally.

SIG SAUER® Compatible

We are a national retailer of individual components and not all products depicted on this website are legal in every state. Shipping of various products found on this website are prohibited to some states (such as California, Connecticut, District of Columbia, Hawaii, New Jersey, New York, Rhode Island, and Washington). The information, pictures, text or products presented on this website are not a representation by us, and should not be understood by you, that any product or completed firearm is legal to assemble or own in your state of residence. We encourage each and every builder to perform their own research about the state and federal laws that apply to them. It is your responsibility to understand the law and we encourage you to consult with an attorney or your local ATF representative.