Specna Arms SA-B01 ONE™ M4 AEG in Black

Specna Arms SA-B01 ONE™ M4 AEG Airsoft Rifle in Black

Key Features

- Full metal M4-style receiver with durable alloy construction and steel reinforcement in key areas.

- Enter & Convert™ quick-change spring system for adjusting muzzle velocity.

- Reinforced Version 2 gearbox with 8mm ball bearings and upgraded steel gears.

- Adjustable rotary hop-up for improved BB range and accuracy.

- Removable carry handle with 20mm top rail for fitting red-dot sights and optics.

- Includes a 300-round high-capacity magazine and additional M90 spring.

- Adjustable stock, 14mm CCW barrel thread and semi/full-auto firing modes.

Classic M4 Looks, Solid Metal Construction and Upgraded Internals – The Specna Arms SA-B01 ONE™ Means Business!

Description.

The Specna Arms SA-B01 ONE™ M4 AEG is a proper old-school M4 with the sort of internal upgrades that make a real difference on the airsoft field. No oversized handguard, no unnecessary extras. Just a traditional military-style airsoft rifle with a solid metal body, dependable electric operation and plenty of room for future upgrades. If you're after a realistic M4 BB Gun that feels substantial in your hands, this one deserves a closer look.

Part of the popular Specna Arms ONE series, this Airsoft AEG weighs approximately 3.5kg, giving it a reassuringly solid feel. The receiver, outer barrel, buffer tube and sling attachment components use metal construction, while the stock, pistol grip and handguard are made from tough polymer. Steel components reinforce important areas, including pins and sling attachment points. The result is an airsoft gun that feels much closer to a military-style carbine than a lightweight plastic replica.

Traditional M4 Styling with Practical Features

Starting at the front, the SA-B01 features a classic M4 flash hider fitted to a 14mm counter-clockwise (CCW) barrel thread. This means you can replace the standard flash hider with a compatible airsoft suppressor or tracer unit. Handy if you fancy changing the appearance of your rifle later on.

Moving backwards, you'll find the familiar two-piece M4 polymer handguard. It keeps the rifle's traditional appearance while providing access to the front battery compartment. The handguard can also be replaced with compatible aftermarket M4 furniture, although some conversions may require additional components or modifications.

The metal upper receiver features a removable carry handle, complete with traditional rear iron sights. Remove it and you'll uncover the top accessory rail, ready for a compatible red-dot sight, holographic-style optic or scope. It's a straightforward arrangement that lets you keep the classic military look or modernise the rifle without much fuss.

There's also a metal sling attachment plate positioned near the rear of the receiver, allowing you to fit a suitable single-point sling. The adjustable stock lets you shorten or extend the rifle to suit your build, equipment and preferred shooting position. With a minimum length of approximately 800mm and an extended length of 880mm, it's a comfortable size for general woodland skirmishing.

Upgraded Version 2 Gearbox – More Than Just Good Looks

Inside the Specna Arms SA-B01 sits a reinforced Version 2 gearbox, the familiar gearbox design found in many M4-style electric airsoft assault rifles. Specna Arms has fitted this upgraded version with reinforced steel gears, 8mm ball bearings, a steel spring guide and a lightweight polymer piston.

Other internal improvements include an aluminium sealed piston head, metal cylinder head and metal air-seal nozzle. These components work together to support consistent compression and reliable operation. Silver-plated wiring helps reduce electrical resistance, while the familiar V2 layout gives experienced airsofters plenty of options when it comes to future servicing and upgrades.

One particularly useful feature is the Specna Arms Enter & Convert™ quick-change spring system. Rather than stripping the entire gearbox to replace the main spring, you can access the spring system after removing the gearbox from the receiver. It's still a job that requires some disassembly, but considerably less hassle than a conventional gearbox rebuild.

The standard spring produces approximately 410 FPS, while the included M90 spring can reduce muzzle velocity to around 310 FPS. Actual results depend on the setup and BB weight. Always check your site's FPS limits before playing, particularly as the standard spring may exceed the limits at many UK airsoft venues.

Adjustable Hop-Up and 300-Round Magazine

The SA-B01 features an adjustable rotary hop-up unit paired with a 350mm inner barrel. Hop-up applies backspin to the BB, helping it travel further before dropping. The rotary adjustment makes it easier to fine-tune your shots for different BB weights and playing conditions.

You'll also receive a 300-round metal high-capacity magazine, giving you plenty of ammunition for longer games. The rifle accepts many standard M4 AEG magazines, including compatible options from brands such as King Arms, MAG, SRC and others. As always, magazine fit can vary slightly between manufacturers.

The rifle offers both semi-automatic and fully automatic firing modes. There's no electronic trigger unit or MOSFET fitted as standard, so you're getting a conventional mechanical AEG setup that's familiar to anyone who's worked on an M4 gearbox.

Battery Compatibility and Everyday Use

The SA-B01 uses a small Tamiya battery connector and supports suitable NiMH, LiPo and LiFe battery configurations. A 7.4V LiPo battery is a sensible choice, particularly when using the included M90 spring. Battery dimensions matter too, so check that your chosen pack fits the available compartment.

Neither a battery nor a charger is included, meaning you'll need to purchase these separately.

For someone wanting a traditional-looking M4 electric rifle with sturdy externals and upgrade-friendly internals, the Specna Arms SA-B01 ONE™ offers a very appealing package. It's equally worth considering as a first serious airsoft rifle or as a classic M4 addition to an existing collection.

Other Great Features are,

- Functional bolt catch mechanism for added realism.

- Anodised metal components for improved corrosion resistance.

- Durable exterior finish applied after surface preparation.

- US Navy-style markings on the magazine well.

- Compatible with a wide range of aftermarket M4 AEG accessories.

- Adjustable hop-up suitable for different BB weights.

- Steel reinforcement in important mechanical areas.

- Traditional M4 styling with a removable carry handle.

In the box:

- Specna Arms SA-B01 ONE™ M4 AEG Airsoft Rifle in Black.

- 300-round high-capacity magazine.

- Removable carry handle with iron sights.

- Additional M90 main spring.

- Battery and charger are not included.

Specifications

Manufacturer: Specna Arms

Model: SA-B01 ONE™

Product Code: SPE-01-004032

Platform: M4-style airsoft assault rifle

Colour: Black

Power Source: Electric AEG

Construction: Metal alloy, steel components and polymer

Weight: Approximately 3500g

Length: 800mm–880mm

Inner Barrel Length: 350mm

Gearbox: Reinforced Version 2

Bearings: 8mm ball bearings

Spring System: Enter & Convert™ quick-change spring

Muzzle Velocity: Approximately 410 FPS with standard spring

M90 Spring Velocity: Approximately 310 FPS

Hop-Up: Adjustable rotary type

Magazine Capacity: 300 BBs

Firing Modes: Safe, semi-automatic and fully automatic

Barrel Thread: 14mm CCW

Battery Connector: Small Tamiya

Battery Compatibility: Suitable NiMH, LiPo and LiFe batteries

MOSFET / ETU: No

Blowback: No

Battery Included: No

Charger Included: No

Important: When using the included M90 spring, we recommend a 7.4V battery to help avoid potential gearbox malfunctions. Always have the rifle chronographed before use to ensure it complies with your airsoft site's power limits.

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Sku :

SPE-01-004032