FN 509 Compact 9mm
Model: 66-100815
FN 509 Compact 9mm
Model: 66-100815
Full Specifications
About This Firearm
FN built the 509 Compact around the same manufacturing standards that won the U.S. Army's Modular Handgun System contract. The cold hammer-forged stainless barrel and FNC (ferritic nitrocarburizing) slide coating give it corrosion resistance and barrel life that most polymer compacts do not match. The hi-viz front sight picks up faster in dim conditions than standard three-dot setups. At 25.5 oz with a 3.7" barrel and 15-round capacity, the footprint sits close to the S&W M&P 2.0 Compact.
The 5.5 lb trigger is average for striker-fired compacts. The Springfield Hellcat Pro holds the same 15 rounds at 21 oz, saving 4.5 oz of carry weight. What the 509 Compact offers instead is build quality you can verify by feel: the slide-to-frame fit is tight, the controls are crisp, and the FNC coating resists holster wear better than standard nitride finishes. Owners who prioritize long-term durability over the lightest possible carry weight find the 509 Compact holds up after thousands of rounds with minimal maintenance.
Best For
Strengths & Limitations
- Cold hammer-forged stainless barrel with FNC slide coating provides better barrel life and corrosion resistance than standard nitride finishes found on most polymer compacts.
- Hi-viz front sight is faster to acquire in low light and under stress compared to basic white-dot sights on the S&W M&P 2.0 Compact and similar competitors.
- The 5.5 lb trigger is average for striker guns. The S&W M&P 2.0 Compact has a comparable pull weight but a flatter trigger shoe that some shooters prefer. Neither gun matches the CZ P-10 C's 4.5 lb break.
- No optic cut on the standard model. The 509 Compact Tactical variant adds factory optic mounting, but the base model requires aftermarket slide milling to run a red dot.
- At 25.5 oz, it weighs 4.5 oz more than the Springfield Hellcat Pro while matching its 15-round capacity. The build quality difference is real, but the weight gap matters during daily carry.
Category Rankings
How the FN 509 Compact 9mm ranks among compact 9mm Luger handguns.
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Frequently Asked Questions
Does the 3.7" barrel provide enough velocity for defensive ammo?
Yes. Federal HST 124-grain hits about 1,100 fps from a 3.7" barrel, which is plenty for reliable expansion. The velocity loss versus a 4" barrel is about 20-30 fps. Modern defensive loads are designed to work from barrels as short as 3". The 3.7" barrel gives you full performance from any quality hollow point.
What is the FNC coating and why does it matter?
FNC stands for ferritic nitrocarburizing, a surface hardening process that creates a corrosion-resistant layer on the slide. It outperforms standard Tenifer and basic nitride finishes for long-term resistance to holster wear, sweat, and humidity. The practical difference shows up after a year or two of daily carry, where the FNC-coated slide keeps its finish while standard coatings show wear marks at contact points.