What is a modular handgun? Check this out - Mirzon
This video explains the concept of modular handguns, using the Sig P320 as a primary example. It highlights that the serial number is located on the fire control unit (FCU), which is distinct from traditional frame-mounted serial numbers found on firearms like Glocks. The video demonstrates a basic field strip to show the separation of the FCU from the grip module, emphasizing how different grip modules can alter the firearm's ergonomics and aesthetics.













