SA M4 Carbine M-LOK (SA-F03 FLEX™ Gen2) - Black / Tan

Specna Arms FLEX™ Series M4 Airsoft Rifle

Looking for the perfect AEG M4 rifle with powerful internals, lightweight build, and an affordable price? Need the best weapon for beginners or a lightweight CQB arena beast? Want a universal rifle with adjustable performance for CQB and woodland skirmishes, accurate in close combat and offering excellent range outdoors? The AEG assault rifle M4 in the entry-level FLEX™ series by Specna Arms focuses on lightweight nylon body design while ensuring top-quality fit and finish. The body is reinforced with fiberglass and is more durable than common zinc alloy bodies found in cheap replicas, appreciated not only by beginners but also by advanced players who prefer fast-paced speedsoft action where every gram matters. This type of body can also be found on CZ Scorpion Evo or MP7 replicas.
The FLEX series is basically the sibling of the CORE line, which features CNC metal handguards, while the FLEX series has nylon handguards instead. The Gen2 internals are top-notch, featuring the reinforced QSC AETHER™ V2 gearbox (the same as in the flagship PRIME series) and the MAGNUS™ hop-up chamber with TDC pressure. Electronic control is handled by the Gate X-ASR Mosfet.

FLEX™ Gen2 Internal Parts

The M4 Carbine M-LOK (SA-F03 FLEX™ Gen2) replica is equipped with the MOSFET X-ASR module from Polish company GATE. It ensures safe switching that protects internal parts, improves trigger response, extends battery life, and increases the weapon’s RoF while allowing safe use of Li-Pol batteries 7.4V and 11.1V. With integrated status LEDs, the module can even diagnose basic faults in the rifle. The rifle also features a fully reworked reinforced gearbox named ÆTHER, capable of handling AEG springs up to M140. Accuracy is ensured by a 6.03 mm inner barrel combined with a Helium Flat-Hop bucking in the redesigned MAGNUS™ chamber with TDC system.
It also includes the QSC ESA spring quick-change system, allowing you to easily install stronger or weaker springs as needed. The spring can be replaced without removing the gearbox from the body, simply through the buffer tube.

External Build of M4 Carbine M-LOK (SA-F03 FLEX™ Gen2)

The Specna Arms M4 Carbine M-LOK (SA-F03 FLEX™ Gen2) replica stands out with a high-quality nylon body featuring a matte finish for a realistic appearance. Reinforced with fiberglass, it is both durable and lightweight. The outer barrel is made of metal, while screws, dust cover, and pins are even steel components. The ergonomic AR15 design and modern construction guarantee comfortable handling and easy operation, making this rifle a perfect fit! The M-LOK handguard allows mounting accessories such as a grip, AN/PEQ box, flashlight, and more. With an adjustable Crane-type stock, this replica is ready for different scenarios and can hold various batteries (Buffer stick, Nunchuck, or Crane). Overall, this rifle combines lightweight build and excellent internals with an attractive price point.

Polymer body parts:

• body
• buffer tube
• handguard
• pistol grip, stock, and sights (same as EDGE series)

Metal parts:

• outer barrel with 14 mm CCW thread
• flash hider
• charging handle for hop-up adjustment
• screws, pins, and small parts are steel-made

Technical Specifications

• Power source: AEG
• Material: Nylon, polymer, metal
• Length: 710–790 mm
• Weight: 2260 g
• Muzzle velocity: 120 m/s (1.48 J)
• Inner barrel length: 270 mm
• Inner barrel diameter: 6.03 mm
• Hop-up: Adjustable, TDC
• Fire modes: Semi, Full Auto
• Thread: 14 mm CCW
• Handguard: M-LOK
• Recommended battery: 11.1V Li-Pol (not included)
• Connector: T-Dean
• Compatible battery types: Crane (Buffer stick, Nunchuk)
• Magazine capacity: 300 BBs (Hi-Cap)
• Motor type: Carbon

Package Contents

• Specna Arms M4 AEG rifle
• 300 BBs Hi-Cap S-MAG magazine
• Folding sights
• Spare weaker spring (M90) for CQB
• Specna Arms stickers
• User manual

Warnings

• Some manufacturers’ springs are overrated (e.g., an M130 spring may perform like M140–150), potentially exceeding the declared gearbox durability. We recommend using only Specna Arms springs. For other brands, choose M120-rated springs to avoid possible damage from mislabeled parts.
• When replacing a spring with progressive (irregular) coils, ensure that the tighter coil end faces outward on the spring guide.
• Never store the replica with a connected battery.