Modular Chassis Insert for SIG SAUER® P320™

The Modular Chassis Insert for SIG SAUER® P320™ comes complete with essential parts as described: The 80% frame insert for the Sig P320 pistol. Here it is, folks -- the latest and greatest in the world of 80% pistol frames: The MUP-1 Fire Control Group Insert. This is the unfinished firearm component of the modular (and wildly popular) Sig Sauer P320. With this one insert, you can configure a custom P320 from scratch in multiple calibers, frame sizes, and barrel lengths. Made from high-quality stainless, just like Sig Sauer's factory frame inserts, the MUP-1 provides incredible tolerances and reliability, with OEM and aftermarket parts compatibility. That means you'll use all the same pins, springs, chassis, barrels, slides, and other components for the P320 to assemble your finished MUP-1 insert. 80% P320 Frame Insert Specs & Features Precision-machined from quality 316 stainless Compatible calibers: 9mm, .40 S&W, .357 SIG, .45 ACP Compatible Frames: P250, P320, EXO-1 chassis Other Required Components P320 Grip Module P320 Lower Parts Kit P320 Slide Parts NOTE: The MUP-1 is an unfinished firearm receiver/frame insert. It is not functional in its current state and cannot be made functional with any components without first being fabricated by you, the end user. SHIPPING RESTRICTIONS APPLY. Although legal under federal law, the MUP-1 frame insert is not available for sale to certain cities and states. You must read our shipping restrictions before attempting order. Orders placed by individuals who lived in a restricted state will be cancelled, and a 10% restocking fee may be deducted from your refund.

No. This product is a part or accessory and does not require an FFL for purchase or shipping.

While Modular Chassis Insert for SIG SAUER® P320™ is legal in most states, always verify your local laws before placing an order. We comply with all state regulations.

In most cases, yes — Glock-compatible frames are designed to accept Glock OEM and compatible magazines. Always confirm fitment in the product details.

That depends on your state’s concealed carry laws. Once properly serialized and registered, carrying may be allowed under state law.

We ship all over the USA within 1–3 business days. You will receive tracking once shipped. Delivery times vary by carrier and region.