The Sig Sauer P320 Fire Control Unit (SIG part no. 8900161) is the serialized core of the P320, the part that carries the trigger group and serial number, finished in Black DLC. It is part of SIG’s Custom Works program for building a P320 from the inside out, and it fits P320 grip modules, slides and barrels in 9mm, .40 S&W and .357 SIG. The stainless steel unit has a skeletonized flat trigger and a striker-fired action, and it carries a custom FCU serial number. Sig Sauer sells it as the starting point for a custom P320 build.

Key Specifications

• The unit fits 9mm Luger, .40 S&W and .357 SIG P320 configurations.
• The finish is Black DLC, a hard coating on the stainless steel unit.
• The material is stainless steel.
• The action is striker fired, as on the P320 platform.
• The trigger is a skeletonized flat trigger.
• Height is 2 inches, measured from the highest point on the FCU to the bottom of the trigger.
• Length is 4.25 inches.
• Width is 1.375 inches, measured from slide catch to slide catch.
• Each unit carries a custom FCU serial number in the format FCU followed by six digits.

Frequently Asked Questions

What calibers does this fire control unit support? SIG lists 9mm Luger, .40 S&W and .357 SIG, and the unit is compatible with P320 post-upgrade accessories in those calibers.

What serial number does this unit carry? SIG gives each unit a custom serial number in the FCU followed by six digits format.

What finish does this one have? This is the Black DLC unit. SIG also lists a gold Tin PVD fire control unit under a different part number.

Buy the Sig Sauer P320 Fire Control Unit, Black DLC

If you are building or rebuilding a P320 around a new grip module or slide, the fire control unit is where the build starts. Order it from our Lubbock, Texas gun shop for fast, insured shipping to your FFL, and see more handgun frames while you are here.