FN 509

History

FN Herstal entered a polymer-framed, striker-fired pistol derived from the FN FNS in the XM17 Modular Handgun System competition initiated in September 2015. After SIG Sauer won in January 2017 with a modified P320, FN America brought a version of their entry, now called the FN 509, to the commercial market. Retired Delta Force operator Larry Vickers was consulted during early development. FN America stated that over a million rounds of ammunition were used during development and testing.

Design

The FN 509 has a stainless steel slide with a ferritic nitrocarburizing finish and a polymer frame. The barrel length is 4.0 in with a full-sized grip. Serrations on both front and back of the slide aid manipulation.

A Picatinny rail sits forward of the trigger guard. The backstrap accepts interchangeable inserts: one arched and one flat. The pistol operates with a double-action trigger and has magazine releases and slide locks on both sides.

Instead of a manual safety, it uses an integrated trigger safety of the articulated type, part of four passive safety systems: a striker block, a drop safety, a trigger disconnect, and a trigger safety lever. Standard magazines hold 17 rounds; 10-round magazines are available for states with high-capacity bans. The FN 509 is primarily chambered in 9×19mm Parabellum, with other calibres offered.

Variants

Several FN 509 variants exist. A Tactical model has a 4.5 in threaded barrel, raised suppressor sights, a low-profile optics mounting system, and 17- or 24-round magazines. A midsize model has a 4.0 in barrel and 15-round magazines. A Compact MRD variant has a 3.7 in barrel, 12- or 15-round magazines, and a low-profile optics mounting system.

The FN 503, introduced in March 2020, is the subcompact model. The FN 502, introduced in September 2021, is the .22 variant. The FN 510 (10mm Auto) and FN 545 (.45 ACP) were introduced in 2023.

Did You Know?

• The FN 509 is the standard-issue sidearm (MRD-LE variant) of the Los Angeles Police Department as of 2021.
• The FN 509 is the standard-issue sidearm (MRD-LE variant) of the Waterbury Police Department of Waterbury, Connecticut as of 2024.