FN Herstal FN 509 GBB Airsoft Pistol – Optics and Suppressor Ready
The FN Herstal FN 509 GBB Pistol is a fully licensed Green Gas airsoft sidearm manufactured by Double Eagle under licence from FN Herstal, granted by Cybergun. Combining authentic markings, a durable reinforced mechanism and modern accessory compatibility, this gas blowback pistol is built for players who demand realism and dependable field performance.
Designed for tactical flexibility, this version of the FN 509 is supplied ready for the installation of an RMR-footprint red dot sight. Its threaded outer barrel features a 14mm CCW thread, allowing compatible suppressors and tracer units to be fitted without extensive modification.
Fully Licensed FN Herstal Design
The aluminium slide carries authentic FN Herstal markings, including the FN logo, 509 model designation and 9x19 calibre marking. These licensed details give the replica a realistic appearance that will appeal to collectors, milsim players and anyone looking for a faithful FN-style airsoft pistol.
Front and rear slide serrations provide a secure gripping surface when charging the pistol, clearing the chamber or performing reload drills. Fibre-optic mechanical sights offer a bright and easy-to-acquire sight picture in both indoor CQB environments and outdoor games.
Optics-Ready Slide and 14mm CCW Threaded Barrel
The optics-ready slide supports RMR-pattern micro red dot sights through the included footprint adapter. Adding a compact red dot can significantly improve target acquisition speed, especially during fast CQB engagements or when transitioning from a primary replica.
The 14mm CCW threaded barrel provides compatibility with a wide range of airsoft suppressors and tracer units. Explore compatible accessories in our red dots and scopes collection and airsoft accessories collection.
Realistic Gas Blowback Performance
Powered by Green Gas, the FN 509 features a strong blowback action that cycles the metal slide with every shot. The realistic recoil impulse, moving slide and functional controls create a more immersive shooting experience while supporting practical reload and weapon-handling drills.
The dual-spring recoil system promotes smooth slide movement and improves stability during repeated firing cycles. Its reinforced internal mechanism incorporates steel components, bearings and durable locking elements to increase reliability during intensive use.
Ergonomic Ambidextrous Controls
The FN 509 is designed to remain comfortable and intuitive for both right- and left-handed players. It features an ambidextrous slide release and magazine release, making control manipulation easier from either side of the pistol.
The nylon-reinforced polymer frame includes a textured ergonomic grip for secure handling with bare hands or tactical gloves. Interchangeable grip panels are included, allowing the grip profile to be adapted to the user’s hand size and personal preference.
Accessory Rail for Tactical Equipment
An integrated lower accessory rail allows the installation of a pistol torch or laser aiming device. This makes the FN 509 particularly suitable for low-light CQB games, indoor training environments and tactical secondary-weapon setups.
For additional sidearm equipment, browse our airsoft pistols, airsoft holsters and Green Gas and CO2 collection.
Key Features
- Fully licensed FN Herstal markings
- Green Gas-powered gas blowback operation
- Metal slide with front and rear serrations
- Optics-ready RMR-type mounting footprint
- 14mm CCW threaded outer barrel
- Fibre-optic mechanical sights
- Nylon-reinforced polymer frame
- Ambidextrous slide and magazine releases
- Integrated accessory rail for lights and lasers
- Textured ergonomic grip
- Interchangeable grip panels included
- Reinforced mechanism with steel components
- Dual recoil spring system for smoother cycling
- Adjustable Hop-Up system
- 21-round Green Gas magazine
Package Contents
- FN Herstal FN 509 GBB pistol
- 21-round Green Gas magazine
- RMR-footprint adapter
- Additional mechanical sight set
- Interchangeable grip panels
- Allen key
This gas blowback airsoft pistol requires regular cleaning, lubrication and maintenance using products specifically designed for gas-powered airsoft replicas.
Technical Specifications
| Manufacturer |
Double Eagle |
| Licence |
FN Herstal / Cybergun |
| Platform |
FN 509 |
| Power Source |
Green Gas |
| Blowback |
Yes |
| Fire Mode |
Semi-automatic |
| Colour |
Black |
| Slide Material |
Aluminium |
| Frame Material |
Nylon-reinforced polymer |
| Internal Components |
Steel and metal components |
| Overall Length |
20 cm |
| Weight |
750 g |
| Muzzle Velocity |
Approx. 300 FPS |
| Hop-Up |
Adjustable |
| Inner Barrel Length |
94 mm |
| Magazine Capacity |
21 rounds |
| Magazine Type |
Low-cap gas magazine |
| Barrel Thread |
14mm CCW |
| Optics Compatibility |
RMR-type footprint |
