Sig Sauer CALX320F40BSS P320 Full Size X-Change Kit 40 S&W Sig 320 Handgun Black

This is a great, but not inexpensive, way to turn your FCU or your 9mm P320 into a .40 S&W version of the Sig P320. Sadly, it only comes with one 14-round magazine and additional magazines are expensive, too. If you search around, you can also find 18-round official Sig .40 S&W magazines. The beauty of the FCU and/or modular platform is that you can swap around. Once you have the .40 slide, you can put it on any 9mm/.40/.357Sig grip module and turn your .40 into something smaller, or different color, or whatever you wish. You can, of course, buy slides alone and save but this kit with the slide, grip module, and mag was a great way to get started. The only down side is that Sig used to ship these X-Change kits in a blue, hard-plastic, carrying case. Now they're shipped in a cardboard box with a cutout foam insert. The foam is nice packaging for shipping and storage but it would sure be nice if it came in a hard case like they did at one time. Overall, I love the P320 for itself as a firearm and also as a modular platform that I can, with a couple of FCUs, purchased separately or as part of a factory firearm, swap around to any caliber in the 9mm/.40/357Sig line and in any color or size I want.