For decades, firearms came in one size and if you didn't fit into that size it was likely difficult for you to find a pistol, rifle or shotgun that fit properly.

That’s why SIG SAUER developed the P320—and later P365—line of handguns. The P320 was designed to be a modular platform, having the ability to change calibers and sizes to best fit the end user’s needs. This is achieved by removing the slide, barrel and guide rod and then the Fire Control Unit (FCU). The process is quick, safe and easy, and can be done yourself, without the need to take your gun back to a dealer or an armorer.

With a removable FCU as the “guts” of the handgun, any shooter of any size and skill level could now tailor their firearm for their body size, intended use and even their sense of style. Now shooters with small or large hands could simply change the grip module to one that perfectly fits perfectly into their hands, which in turn promotes better on-target accuracy. While everyone’s hands and fingers are sized differently, the technique of shooting your gun accurately remains the same: press the trigger while adding as little motion to the gun as possible. If the pistol fits you properly, you are less likely to introduce motion to the muzzle, making for a more accurate shot.

The keys to modularity are a tailored fit—which translates into dramatically better shooting fundamentals—and a multi-use platform that can turn one gun into many.

SIG SAUER Academy Senior Instructor Chris Cavallaro understands the importance of modular pistols and proper pistol fit as he sees the benefits daily with his students. “For competition, for defensive work, and just for training it’s very important to be able to reach the buttons, knobs and levers on the pistol for speed, safety and consistency,” he says.

That made sense to the U.S. military, as well, which purchased the M17 and M18 (based on the P320) as its standard issue pistol. Thanks to the modularity, virtually any service member could find the right fit, making training easier and marksmanship better. In addition to the modularity, the P320 platform’s safety system includes both a striker safety and a disconnect safety. And because of its 3-point takedown safety, owners never again need to pull the trigger to disassemble the pistol.

With the range of grips, slides, barrels and magazine options, units from special operations, to aviators to criminal investigators could now take advantage of the built-in modularity to tailor the M17 or M18 to their specific mission.

And building on the success of the P365, SIG SAUER embedded this same focus on modularity into that platform, allowing self-defense shooters to modify their P365 to their body shape, carry method and environment. So, no matter if it’s the heat of the summer and all you’ve got are shorts and a t-shirt, the dead of winter and you’re carrying under a heavy coat, the modularity-minded P365 can be tailored to fit any carry scenario. 

If you’re in the market for a firearm, it’s crucial that modularity be part of the equation. A handgun that fits properly and can be changed to suit different shooters’ needs makes for a better shooting experience and continued growth in the sport.