The Sig Sauer P320 X-Series slide assembly with 3.9" barrel is a ready-to-run upper for shooters building or upgrading a P320 platform pistol in 9mm Luger. This stainless steel slide comes finished in Coyote Brown and arrives mounted with a Romeo1Pro red dot sight—a solid, no-hassle setup for defensive use, competition, or duty carry without the guesswork of pairing optics separately.
Built on Sig's proven P320 X-Series ergonomics, this slide assembly is a drop-in solution for P320 users who want to modernize their platform with integrated optics mounting. The 3.9" barrel length strikes a balance between capacity and controllability, making it a versatile choice for concealed carry and service-pistol applications alike. The Coyote Brown Cerakote finish resists corrosion while delivering that professional, tactical aesthetic without the premium cost of exotic coatings.
The included Romeo1Pro is Sig's fieldproven 1x red dot, designed specifically for handgun mounting. Pairing it directly to the slide means you're getting a cohesive system tuned for the P320 platform—no adapter rings, no alignment headaches. Whether you're running this on an existing P320 frame or building fresh, you'll appreciate the clean integration and the confidence that comes from factory-matched components.
| Brand | Sig Sauer |
| Model | 8900279 |
| Caliber | 9mm Luger |
| Barrel Length | 3.9" |
| Slide Material | Stainless Steel |
| Finish | Coyote Brown |
| Included Optic | Sig Romeo1Pro |
| Platform | Sig Sauer P320 X-Series |
This is a P320 X-Series slide assembly, so it's designed to work with P320 X-Series frames. Verify your frame model before ordering to ensure compatibility.
The Romeo1Pro arrives mounted on the slide. You'll want to zero it to your point of aim before relying on it for carry or duty use, but it's fully functional from the package.
This is a slide assembly, so you'll need a compatible P320 frame, fire control group, and magazine to assemble a complete pistol. Consult Sig's documentation to ensure all parts are compatible.
The Coyote Brown Cerakote finish is corrosion-resistant and durable for regular carry and use. Like any finish, it will show wear over time with heavy use, which is normal and does not affect function.
Sig Sauer
