The P320 by Sig Sauer® was a great addition to our industry. It introduced the idea that you could have one pistol, but that you could modify it to be adaptable to any carry situation. They did it by defining the insert or the “guts” of the P320 as the legal “firearm,” so that you could modify everything around it, thereby changing its carry size and profile. If you’re looking for a new pistol with that same end-all/be-all feel to it, that same one-and-done idea, but you want to build it yourself and without that new pistol price, then you too need to start with the piece the government considers the “firearm.”

We’re excited to bring you that piece. The P320-compatible MUP-1 comes to you in 80% form. When you’ve completed work on it, it too will legally be defined as the “firearm” itself, which will then make it as modular as the expensive one you’d buy at your LGS. When outfitted with P320 compatible parts, the insert can be used to make a 9mm, 40 S&W, 357 SIG, and 45acp (with slight modifications).

Kit Includes

1 P320 80% Insert
Insert made from 316 Stainless Made In The USA

Compatible Firearms:

Sig Sauer P320 – Full Compatibility
Sig Sauer P250 – Grip Modules
Made from 316 Stainless in the USA

Tooling Sold Separately

Shipping Restrictions

This item is restricted from shipping to: New Jersey, New York, Hawaii, Connecticut, Rhode Island, Washington D.C., Maryland, Illinois, California, Washington, Colorado, Pennsylvania, Puerto Rico, Massachusetts, Delaware


Due to recently changed ATF regulations, We cannot legally ship our Sig P320 80% Jig & Sig P320 MUP -1 Insert on the same order. The Sig P320 Jig & Sig P320 Mup-1 Insert must be purchased on our website as two separate orders so we can stay in compliance with the new regulations. You cannot order an 80% Lower and jig-related product on the same order. Thanks