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CALIFORNIA: No sales/shipping of firearm parts due to CA AB 1263 requirements effective 1/1/2026.Any California order will be canceled and refunded.Lower Parts Kit (LPK)
for SIG Sauer P320
9mm, .40 S&W, and 357 SIG
Fire Control Unit (FCU) Parts KitDescriptionThis premium lower parts kit for the SIG Sauer P320 fire control unit (FCU) includes everything needed to complete one\'s SIG Sauer or MUP 1 build. All of the components in the set are equal or better than the OEM versions.This is a best-of-breed build solution featuring parts made from polymer, billet steel, or high-quality stamped steel versus MIM (Metal Injection Molding). It elevates the quality of the fire control unit components to an unparalleled level.All of the parts shown are included except the actual FCU, which is a regulated component. The parts displayed in the official SIG SAUER factory parts diagram directly below this paragraph, each with the factory number circled in orange beside it, are part of this kit.Don\'t settle for less in your build. Choose a solution that will provide you with the highest performance, unmatched durability, and unsurpassed reliability.
NotesThe buyer will receive a completion kit identical to the one seen in the photos below. Feel free to message through the mailing system for answers to any questions.
Above images: Photos of a completion kit identical to one the winning buyer will receive.
All photos and text Copyright © 2026 by Phil Steinschneider and Cool F/X™
