SIG CALIBER X-CHANGE KIT P320 M18

Description

The Sig Sauer Caliber X-Change Kit for the P320 M18 is built for P320 owners who want to run the M18 configuration without purchasing a second serialized firearm. The kit converts any compatible P320 Fire Control Unit — the serialized component you already own — into a functionally complete M18 platform. What you receive is the complete slide assembly, a 3.9-inch barrel, recoil spring, and grip module in Coyote Tan finish, along with three magazines. The Fire Control Unit is the one thing not included, which is the point: everything around it changes, the serial number stays with you.

The magazine count matters here in a practical way. Two of the three included magazines are 21-rounders, giving you a meaningful capacity advantage during range sessions or training without needing to source additional magazines separately. The single 17-round magazine suits carry configurations where the grip module is the limiting factor for concealability.

The 3-dot sights provide a straightforward sight picture that works well in both low-light and daylight conditions without requiring a separate optic purchase to get the pistol into service. The M18 slide on this kit is also optic-ready, so mounting a red dot is a straightforward option if your training requirements call for it.

This kit is a practical solution for shooters who already own a P320 and want M18 configuration for duty training, standardization with military-pattern gear, or simply to run a proven military-specification setup without redundant serialized hardware.