The Sig P320 Compact is a compact enough gun to be carried covertly or frequently used. Consider this to be the Glock 19 of the Sig Sauer lineup. FCU is such a special feature that it deserves a review all by itself. It is a true testament to the design team at Sig Sauer that it offers the modular capabilities that it does. It is the most crucial component because it houses the serial number and the “brains” of the firearm. The FCU serves as the “brain” of the weapon, and you get to design the rest of it around it. When switching to other frames, the trigger and controls stay with the unit. It’s challenging to pinpoint the trigger—no pun intended—for this. Physically, it’s simple to place your trigger finger where you need it, but it can be challenging to decide whether or not you like the trigger. The grip on the Sig Sauer P320 is among my main issues with it. This pistol stands as one of the best pistols of our time.