SA M4 Carbine M-LOK (SA-P20 Prime™ Aster II ETU) with Brushless Motor – Chaos Bronze

M4 Carbine M-LOK (SA-P20) by Specna Arms in Prime™ series and Chaos Bronze finish.

Receiver with Nano Coating for scratch resistance.

Reinforced AETHER™ gearbox with upgrade parts and Brushless motor.

Gate ASTER II Bluetooth® ETU and Quantum Trigger 2.

MAGNUS™ hop-up chamber with TDC adjustment, Flat bucking, and a 6.02mm barrel.

3 springs included (M90, M115, M135).

M4 Rifle, History of the Real-World Predecessor

The M4 is a compact automatic rifle developed in the United States based on the popular M16 assault rifle, with a focus on the need for a lighter and shorter version suitable for urban combat.
In the 1960s, the M16 rifle, developed by Armalite for the U.S. military, served as the base design for the future M4 rifle. In the 1980s, the first M4 prototypes appeared, featuring a shorter barrel and telescopic stock, improving the rifle’s maneuverability in confined spaces.
In the 1990s, the M4 was officially adopted by the U.S. armed forces as the standard assault carbine, replacing older models like the M3 and M9.
The M4 rifle is characterized by its ability to fire single shots and bursts. It quickly became popular among soldiers due to its lightweight, compactness, and reliability. It was widely used in conflicts in Iraq and Afghanistan and became an iconic weapon of the modern U.S. military. Besides the standard model, many M4 variants exist, equipped with different accessories and upgrades to meet the specific needs of military units.
This modernized AEG rifle, the M4 Carbine M-LOK (SA-P20), in the top-tier Prime™ series from Specna Arms, boasts excellent body craftsmanship and is equipped with a M-LOK handguard that offers a more secure mounting system on the weapon while being easier to grip.

What Does the M4 Carbine M-LOK (SA-P20 Prime™) from Specna Arms Offer?

Prime™ is the top tier. It represents the best, most refined, most upgraded, most perfect, and most reliable that Specna Arms has to offer. In short, Specna decided to take the perfectly fitted body from the Edge/Edge 2.0 series with Nano Coating surface treatment, which boasts increased resistance to scratches and damage, and load it with high-performance upgrade parts. They started with the motor upgrade, specifically a brushless motor housed in a new QD grip for quick access to the motor. The gun also features a completely redesigned ÆTHER gearbox, capable of handling AEG springs up to M140. Inside, you’ll find a Bluetooth ASTER II ETU processor unit, CNC gears with a 16:1 ratio, CNC cylinder and piston heads with CNC nozzle, 8mm ball bearings on the piston and motor gears, and a slide bearing on the sector gear. Accuracy is ensured by a 6.02mm inner barrel, fitted with a Helium Flat-Hop bucking in the redesigned MAGNUS™ hop-up chamber with TDC pressure system.
The package includes 3 different AEG spring strengths, so you can head into a CQB arena with the M90 spring. In under a minute, thanks to the ESA2 quick spring change system, you can install the M115 spring for standard skirmishes or the strongest M135 spring in the package to turn your gun into a precise DMR with excellent range.
If you’re looking for a versatile airsoft gun made from the best components that requires no additional investment, then the Prime™ series is the right choice. From a fast CQB drill to a precise DMR rifle firing single shots, that’s the magic of Prime™. The package includes two S-Mag mid-cap magazines for 125 BBs and a speed loader for easy magazine filling.
If you’d like to learn more about the Prime™ series configuration, we’ve prepared a detailed list of all the important aspects for you.

Gate ASTER II Bluetooth® Processor Unit

This unit ensures safe switching and protects the internal parts, improves trigger response, extends battery life, increases the gun’s rate of fire, and allows the safe use of Li-Pol batteries 7.4V and 11.1V. The battery connector is T-Dean with output to the stock tube.

ASTER II unit features:

• Trigger sensitivity adjustment – 5 optical sensors allow you to set the trigger sensitivity exactly as you desire
• Burst mode adjustment – from 2 to 10 shots, with an interval between shots of just 4ms
• Fire selector adjustment – SAFE – SEMI/BURST – BURST/AUTO and more
• Pre-cocking – pre-cocks the piston immediately after the shot, providing better trigger response in Semi mode
• Rate of fire control (ROF)
• DMR mode – sets a delay between shots in Semi mode
• Smart trigger – ideal in combination with ROF reduction, the first shot is at 100% speed, the remaining shots are reduced as per your selection
• Battery protection and low voltage warning – ASTER automatically detects battery cells and stops shooting when voltage drops to a set level, causing the motor to vibrate
• Smart fuse – protects the motor and itself from overheating or overload
• Active brake – reduces motor wear by gradually braking (instead of immediate stopping)

Gate Control Station Bluetooth App

Thanks to the app for phones with Android, iOS, or computers with Windows/Mac, you can easily configure the processor unit. All functions are clearly visible directly on your phone without the need for a programming card or pressing the trigger. The app also allows you to download the latest firmware to ensure your unit always offers the best performance.

Download link for the app:

• Android
• iOS
• Windows/Mac

Premium External Parts

The rifle boasts high-quality external craftsmanship with a Nano Coating surface treatment, offering increased scratch resistance and damage protection. The matte-painted body gives it an elegant look. The ergonomic AR15 design and modern construction ensure comfortable handling and easy operation. The CNC metal M-LOK handguard allows the attachment of various accessories such as grips, AN/PEQ box, flashlight, etc.
With the adjustable stock Crane, this replica is ready for a variety of game scenarios and can accommodate batteries (types Buffer, Nunchuck, or Crane).
A new feature of the Prime™ series is the redesigned QD grip, allowing quick access to the motor through the folding baseplate of the grip.

Redesigned Specna Arms ÆTHER™ Gearbox

The ÆTHER™ gearbox represents the most durable stock gearbox on the market. The overall reinforced shell is capable of handling the included Specna Arms M135 spring and has been patented by Specna Arms (European patent no. 015044865-0001).

The ÆTHER™ gearbox offers the following features:

• Spring release function (after an action, it’s necessary to release the spring to prevent it from staying compressed and straining internal parts)
• Window for inspecting AoE and the piston pre-cocking level
• Reinforced front end of the gearbox shell
• Trigger travel adjustment
• Centering holes to align the gearbox in the gun’s body

Tuned Internal Parts in the Gearbox

Inside the gearbox, you’ll find CNC steel gears with a 16:1 ratio, providing an ideal balance between great rate of fire and durability when using stronger Specna Arms M135 springs.
8mm J-Cage bearings are ball bearings on the motor and piston gears, while the sector gear features a slide bearing for increased durability. This setup is based on testing various bearing configurations, and in this combination, it achieved the ideal balance between durability and rotation speed.
Reinforced polycarbonate piston with 14 teeth provides ideal gear-to-piston engagement (AoE) and prevents gearbox jamming. It’s durable enough without unnecessarily slowing down the shot.
The piston is fitted with a CNC piston head with enlarged ports for efficient airflow into the CNC double-sealed cylinder head, housed in a ribbed stainless steel cylinder that helps cool the cylinder during automatic fire.
Air is fed into the hop-up chamber via a CNC nozzle mounted on a reinforced tappet plate. Reliable feeding is ensured by a strong tappet spring and a sector gear delay cam.

Precision Trigger Gate Quantum Trigger 2

Quantum Trigger combined with ASTER V2 allows you to set the trigger sensitivity from an absurdly light touch to a full stroke. Version 2 features adjustable reset via the app, durable construction from 7075 aircraft aluminum, and is compatible with the TACTICKER module from Gate for simulating real trigger pull.

What to expect from the Quantum 2 trigger?

• Ultra-fine adjustment – up to 60 levels of trigger sensitivity for the first millimeter of movement, ensuring that every detail of your pull is captured.
• 470 possible sensitivity levels – for the entire movement range, ensuring you can customize the settings to your exact preferences.
• Designed for professionals – the Quantum Trigger is intended for experienced players who demand maximum performance and reliability.
• CNC-machined aluminum – every detail of this trigger is precisely CNC-machined from aluminum, making it not only a powerful tool but also an aesthetic gem.

Brushless Specna Arms Dark Matter 27k Motor

The long brushless Dark Matter™ motor from Specna Arms with 27,000 rpm brings a revolution! The motor provides higher efficiency, better performance, and even increases the rate of fire and response to the trigger.
It offers up to 5x more shots on the same battery than standard motors. (5000+ shots on 11.1V 1000mAh). Additionally, it’s housed in a durable aluminum body, suitable for springs up to M190!

TDC Hop-Up Chamber MAGNUS™ and Helium™ Flat-Hop Bucking with Precision Barrel

The extremely precise polymer chamber features a TDC pressure system. It’s a special design element of hop-up chambers that allows for optimal pressure adjustment on the BB through the hop-up bucking nub. The pressure is applied directly over the barrel window, perfectly perpendicular downwards, rather than at an angle using a lever. This allows players to achieve greater shooting accuracy, a stronger hop-up effect with heavier BBs, and consistency with each shot.
The chamber is fitted with a Helium™ bucking with a Flat pressure system. This bucking is smooth on the inside with no nub, eliminating the issue of BBs curving when improperly installed, while increasing the contact area where the BB touches the bucking, practically covering the entire surface of the pressure segment (nub). This results in higher BB rotation, ensuring greater range and accuracy, and allows the use of heavier BBs.
For those seeking even more, the BBs pass through a precision barrel with an inner diameter of 6.02mm.

ESA2 Quick Spring Change System

The spring can be changed without the need for special tools. No long screwdriver is required, just loosen the stock tube nut to access the QSC spring guide. The spring guide features a ball bearing that facilitates spring compression. The Prime™ series includes 3 springs in the package:

• M90 spring – ideal for CQB and close-range shooting where there is a risk of unnecessary injury to opponents.
• M115 spring – this spring is suitable for most standard skirmishes, where you’ll be shooting at medium ranges.
• M135 spring – the strongest spring, suitable for single-shot long-range shooting as a DMR sniper rifle.

Package Contents:

• Specna Arms Prime™ AEG rifle
• 2 S-MAG mid-cap magazines for 125 BBs
• Battery connector adapter for small Tamiya
• Speed loader
• Folding sights
• Spare weaker spring (M90) for CQB
• Spare stronger spring (M135)
• Specna Arms promotional stickers
• User manual

Warning

• Some third-party springs are significantly overrated (e.g. an M130 spring may perform like M140–150), and their power could exceed the declared durability of the gearbox. We recommend using only the included Specna Arms springs. If using third-party springs, choose a spring rated M120 or lower to avoid damaging the rifle with an overpowered spring.
• If replacing a spring with a progressive (irregular) winding, make sure that the tightly coiled end faces outward on the spring guide—away from the gearbox.
• Never store the gun with the battery connected.
• Never store the gun with the pre-cocking function engaged. Always release the piston forward before storage to avoid damaging the spring. 

Download Link for Gate Control Station (GCS) App

• Android
• iOS
• Windows/Mac

Pairing the App

To pair the GCS app with the ASTER II unit, you must enter its code, which is located on the label on the wiring. Ideally, leave this label on the gun or at least keep it. Without the code, the unit cannot be paired with the app.

Hop-up adjustment wheel

The adjustment wheel for hop-up pressure is very loose from the factory to allow for quick and easy manipulation. However, what one person may find convenient, another may find annoying.
Your friend has thought of everyone, so we’ve included a special O-ring in the package, which can be used to tighten the adjustment wheel, preventing accidental loosening of the pressure setting.