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Sig Sauer P320

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SIG Sauer P320: Evolution and Specs

One of the more notable striker fired pistols to come out of the 2010s was the SIG Sauer P320. Not only is the P320 among the more unique striker fired pistols due to its modular design, but it’s also notable due to the fact that it was selected as the replacement to the Beretta M9 as the US military’s standard issue sidearm.

As a result of its adoption by the US military as well as numerous law enforcement agencies, the P320 has grown in popularity amongst civilians as well. There are numerous IWB holsters and OWB holsters available for the P320 out on the market, as well as a vast array of aftermarket parts and accessories such as improved triggers, sights, and so on.

In this article, we’ll dive into the history and evolution of the P320, and then we’ll explore the specific specs and features of the pistol.

History and Evolution of the SIG Sauer P320

The SIG Sauer P320 is essentially the striker fired version of the hammer fired P250 pistol, and the two guns look nearly identical when viewed side by side.

The P320 was first released to the American market in early 2014 in the 9mm version, and the .40 S&W, .357 SIG, and .45 ACP versions subsequently followed. It immediately gained attention due to its truly modular design which will be discussed in greater detail below.

SIG Sauer entered the P320 as the M17 (full size) and M18 (compact) into the US Army’s XM17 Modular Handgun System, where it competed against numerous other handguns including the Glock and the Smith & Wesson M&P.

In early January 2017, the M17 and M18 were announced as the winners for the U.S. military’s new sidearm to formally replace the Beretta M9. The phasing-in process of the SIG is currently ongoing, and the military plans to procure over 420,000 P320 pistols in total.

Design and Specs of the SIG Sauer P320

The P320 was designed by SIG Sauer to be a fully ambidextrous firearm just like the P250, and to this end, it sports a reversible magazine release and a slide release lever on both sides of the weapon.

But the main standout feature of the P320 is the fact that it is a truly modular handgun. For example, you can remove the fire control system from the pistol and swap it between different slides and frames.

This means that you only need one fire control system, and you can then purchase numerous different frames and slides at lower price points in order to put together full size, compact, carry, and subcompact versions of the pistol, and across different calibers (switching from .40 S&W to .357 SIG or vice versa, however, simply requires a barrel change). It’s this feature that sets the P320 apart from competing striker fired pistols like the Glock 19, S&W M&P, CZ P10C, HK VP9, or the Walther PPQ.

Here are the specs of the SIG Sauer P320:

  • Country of Origin: Switzerland (but primarily manufactured in the USA)
  • Caliber: 9mm Luger, .40 S&W, 357 SIG Sauer, and .45 ACP
  • Capacity: 17 rounds (9mm), 14 rounds (.40 S&W and .357 SIG), 10 rounds (.45 ACP) + extended magazines also available
  • Overall Length: 8 inches
  • Barrel Length: 4.7 inches
  • Weight (with magazine): 29.4 ounces
  • Width: 1.4 inches
  • Height: 5.5 inches


All in all, the P320 represents a solid alternative to other striker fired handguns such as the Glock 19 or Smith & Wesson M&P. Since it’s become firmly established in the firearms world as a successful military and law enforcement sidearm, it is likely that the P320 will be around for many decades to come.

Sig Sauer P320 Inside The Waistband Holsters

Sig Sauer P320 Outside The Waistband Holsters