‘Unmatched Modularity’
Again, those are Sig’s words, but I’ve got to hand it to them. The gun is remarkably modular. Integrated into the design of the P320 is the ability to change out your frame, which is available in small, medium, and large. Now I’m not talking about changing out your backstrap or a small enhancement to your grip. This is the entire grip frame.
This means you can go from a full-size frame to a compact carry frame in just a few easy steps. Think that’s cool? The innovation doesn’t stop there. With readily available conversion kits, you can also change the slide length, barrel, and/or caliber of the handgun!
That’s right, you can buy the 9mm and convert it to a .40 S&W, .357 SIG, and even a .45 ACP. And those different frame sizes I mentioned earlier? Yeah, they work with the conversion kits, too. The secret is in their removable Fire Control Unit, or FCU, which acts a lot like a drop-in trigger unit and functions with all of the conversion kits, barrels, frames, etc. The FCU is the serialized part of the gun, functionally making it the “firearm” in a legal sense.