FN 503 Micro 9mm Luger, 3.1 in Barrel, Striker-Fired, Black Nitride Slide, Fixed Steel Sights — USA Made
The FN 503 is FN America's micro-size 9mm pistol, introduced in 2020 and discontinued by 2023. Built in the USA, it combines a serialized chassis inside a polymer grip module with a black-nitride slide and fixed steel sights in FN 509-compatible dovetails. This compact 3.1 in–barreled, striker-fired design emphasizes durable materials and straightforward controls.
Condition
Overall Condition: Poor condition.
Bore Overall Condition: Good - Clean, well-maintained, minor wear marks.
Bore Rifling: Good Rifling - Intact, well-defined lands and grooves.
Specific Condition Notes: There is significant rust throughout from previous handling and use. The pistol’s dual captive recoil-spring assembly is present (seen separately in the photos) but not installed; the magazine is missing, and the pistol is not currently functional as shown. Please refer to the photos for a clear view of the present condition.
What’s Included
- FN 503 9mm Luger semi-auto pistol (as shown)
The FN 503 is a micro 9mm built around a striker-fired, short-recoil, locked-breech system. Its compact 3.1 in barrel and streamlined profile are paired with fixed steel sights set in dovetails that are compatible with FN 509 sight dimensions, allowing straightforward sight changes if desired.
Construction centers on a polymer grip module over a serialized chassis/FCU, with steel components treated via ferritic nitrocarburizing and a black-nitride slide finish. The frame features molded stippling with traction bars on the front and backstrap for consistent purchase.
The slide includes cocking serrations and an external extractor, and the barrel hood provides a visual loaded-chamber check. Controls are simple and direct, with a left-side magazine release and a trigger safety.
This model has no accessory rail, keeping the profile clean. The original design uses a dual captive recoil-spring assembly on a steel guide rod; see the Condition notes regarding the present but not installed recoil spring assembly on this example.