MUP-1 80% P320 Frame (Sig Sauer® Chassis)

MUP-1 80% P320 Frame Insert – Stainless Steel P320 Chassis

Build your custom SIG P320 platform with the trusted MUP-1 80% Frame Insert—available now at BuyGhostGun.com.

Crafted from durable 316 stainless steel, the MUP-1 is the essential foundation for completing your own SIG P320-style pistol. Designed to accept a wide range of calibers including 9mm, .40 S&W, .357 SIG, and even .45 ACP with minor modifications, this frame insert gives builders the flexibility and strength they need in a truly modular handgun system.

Key Features:

• Precision machined from corrosion-resistant 316 stainless steel

• Compatible with P320 9mm, .40 S&W, .357 SIG, and .45 ACP (with trimming)

• Supports full-size and compact P320 builds

• No FFL required – this is a legally classified 80% frame

Easy-to-Finish Steps:

To complete your MUP-1 insert and prepare it for full assembly, just finish the following:

• Drill the necessary pin holes

• Bend the side rails into position

• Trim the rails to proper length

No milling machine or complicated jigs required—just basic tools, clear instructions, and a little time.

Why Buy from BuyGhostGun.com?

• International shipping available – We ship worldwide

• Fast, discreet delivery

• Premium quality and guaranteed authenticity

• Trusted by builders across the globe

Perfect For:

• First-time DIY gun builders

• Experienced P320 enthusiasts

• Anyone looking for an 80% SIG P320 fire control unit

Start Your P320 Build Today

Order your MUP-1 80% P320 Frame Insert from Buy Ghost Gun and take full control of your custom handgun build. No serial number. No registration. Just you, your tools, and the freedom to build.