Specna Arms SA-K02 ONE™ M4A1 AEG; Kestrel Basic ETU

The M4A1 is the industry standard when it comes to recognisable platforms. The SA-K02 ONE™ boasts full metal construction, a 6,03mm tightbore inner barrel for impressive accuracy potential and the latest rotary HOP-up design. Combined, these features make for a premium-feeling rifle in your hands and shooting downrange!

The Kestrel Basic offers programmable fire modes including 3 round burst and binary trigger, adjustable pre-cocking with 6 levels to choose from and several quality-of-life functions such as low battery warning and cycle completion. The result is a remarkably snappy trigger when pre-cocking is set, the perfect feature for someone who often finds themselves getting outgunned whilst skirmishing. Alternatively, there is nothing quite as satisfying as shooting in 3-round bursts and dominating the battlefield!

The externals of this Specna Arms M4A1 are constructed from a high-quality alloy just like the original ONE™ series, it is sure to withstand the trials and tribulations of any skirmish, indoors or outdoors. The silhouette perfectly echoes the real steel M4A1, if you're a stickler for realism, surely this one meets your high standards. If you're looking for a militaristic M4 that can do it all, the Specna Arms SA-K02 ONE™ M4A1 AEG; Kestrel Basic ETU is the rifle for you!

Starting at the front of this rifle we find an alloy birdcage-style flash hider, this is the most common muzzle device found preinstalled on M4 platforms and is perfect for skirmishing as it protects your outer barrel from damage and vegetation whilst skirmishing in the wild. However, you can remove this muzzle device to reveal 14mm CCW threading. This threading type accepts the most readily available muzzle devices, exchange the bird cage for something sneakier like a suppressor or maybe a tracer unit so you can see exactly where you aim your BBs. Just remember to remove the grub screw in the flash hider before attempting to unscrew it!

Moving down the long 14" outer barrel we come to the front iron sight is based on the standard M4 fixed front post which doubles as the gas block in the real deal. The sight is constructed from alloy and the sight blade is adjustable for elevation using an AR-15 front sight adjustment tool. On the bottom of the front sight, we also have a sling point and bayonet lug which is compatible with most Airsoft M9 bayonet replicas.

The handguard is found just to the rear of the gas block and features 20mm Picatinny rail sections at the 12, 3, 6 and 9 o'clock positions, this is an excellent way to maximise attachment space on an AEG and allows for the most customisation when making your rifle unique to you. The alloy handguard is retained by an alloy handguard cap at the front and what is known as the "M4/M16 Delta Ring" at the rear. The mock gas tube is visible through the upper vent ports, a lovely hint of realism often missed from Airsoft AR replicas. Congratulations Specna Arms, you passed the realism test!

The receiver should be a familiar sight to anyone who has handled an M4/AR-15 platform before, constructed from alloy and matching the real M4A1 receiver style perfectly. This includes the reinforced front pinhole, mil-spec flat trigger guard, magazine release fence and low profile charging handle latch. The magazine release is ambidextrous and found on both the right and left sides of the magazine well, the right side has a push-through design just like a standard M4/AR-15 AEG with a textured surface for optimal traction.

The fire selector is also ambidextrous and the switch is found just above the pistol grip on both sides, offering 3 modes of fire with a 90-degree throw between each. The default fire modes are safe, semi-auto and full auto but with the pre-installed Kestrel Basic ETU, you have the option of using binary trigger instead of semi and 3-round burst instead of full auto. This makes the SA-K02 ONE™ very versatile and ready for any situation you may find yourself in.

The charging handle can be found at the top rear of the receiver and as mentioned, features the milspec low-profile charging handle latch to reduce snagging potential. Pulling the charging handle back will pop the dust cover open and retract the black-finished mock bolt, revealing the rotary HOP-up unit on the right side. The HOP-up allows you to adjust the amount of backspin applied to your projectiles and tune the SA-K02 for different ammo weights, looking for the flattest possible trajectory. When you've completed your adjustments, you can slap the "ping pong paddle" style bolt release catch on the left side of the receiver to drop the mock bolt with a satisfying metal-on-metal "clank".

Up top, we have a 20mm Picatinny receiver rail with a preinstalled rear "ghost ring" iron sight. The rear sight is adjustable for both windage and elevation without requiring a single tool to do it, the dial on the right side adjusts windage (left to right) and the dial below the aperture controls elevation. If you prefer to run an optical sight you can loosen the thumb screws on the left side of the iron sight and remove it to access the full length of your receiver rail. As much as a carry handle would complete the iconic look of the M4A1 build, an ACOG-style optic is much more ideal if you're going for an "in the field" look.

The pistol grip provided on the SA-K02 ONE™ is an "A2" finger-ridged type, with diamond checkering on either side and linear grooves on the rear to provide a comfortable grip. The A2 grip is exactly what an M4A1 replica needs, matching the real steel US Army and SOCOM-issued variant perfectly.

At the very back of the receiver, we can find an ambidextrous "CQD" type sling plate, which allows a single-point bungee sling to be used with the rifle and installed on either the left or right side. This sling plate is constructed from steel, ensuring the substantial strength required to support the weight of the rifle and all the attachments that you mount.

Moving to the rear, we can find a 6-position M4/AR15 buffer tube, constructed from the same alloy as the receiver, keeping the platform strong and durable. The crane battery stock runs on this buffer tube and can be adjusted to any of the 6 positions by holding down the textured adjustment lever on the bottom of the stock and adjusting it to the desired length. On either side of the stock, we can find QD sling sockets, which when coupled with a QD sling stud, can provide a flexible sling set-up with quick-release functionality.

The battery compartment of this SA-K02 is within its stock and we recommend a 7.4v 2600mAh 25C LiPo in a nun-chuck/crane configuration. The battery compartment is accessed through the butt plate of the stock. This is achieved by pushing the two protruding tabs at the toe of the stock together, and then through the stock to the rear, after which the butt plate can be pulled downwards, and removed. With the butt plate removed, you can remove the battery compartment plug, and insert your battery into the buffer tube or crane slots within the stock, connecting it to the Deans connector.

Inside the SA-K02 ONE™, we are treated to the same solid internals as the original, including 18:1 ratio steel gears running on 8mm ball bearing bushings and a steel spring guide with Enter & Convert™ quick change spring functionality. Enter & Convert™ requires the gearbox to be removed from the receiver but doesn't require the gearbox itself to be opened, saving you hassle when it comes to power tuning and minimising the expertise needed.

The highlight of this refined version of the original SA-K02 ONE™ is its Kestrel Basic ETU/MOSFET, offering 6 levels of adjustable pre-cocking, options for 3 round burst and binary trigger along with low battery warning, cycle completion, active braking and low/high voltage cutoff. This means you can crank up the trigger response for super-fast double taps. Also inside is a 6.03mm tightbore inner barrel and rotary HOP-up unit, giving you superb accuracy potential and the latest HOP-up design for M4/AR-15 platforms.

If you want an iconic rifle silhouette and like the idea of alternating between different fire modes with a high-end MOSFET, then the Specna Arms SA-K02 ONE™ M4A1 AEG; Kestrel Basic ETU is exactly what you are looking for. With its full metal construction, preinstalled programmable MOSFET and plenty of handguard rail space, this rifle is definitely worth its price tag!

Features

• Full metal construction
• 6.03mm Tightbore inner barrel - Superb accuracy potential
• EShooter Kestrel Basic ETU Pre-installed - Loads of programmable functions
• 14mm CCW Male threaded outer barrel - Tracer/suppressor ready, Birdcage flash hider pre-installed
• 14" Outer barrel 
• M4/M16 Triangular front sight - Adjustable using an AR sight adjustment tool, completes the iconic silhouette
• Bayonet lug - Compatible with replica M9 bayonets: Big Dragon M16 Training Bayonet | Ghost Dummy Bayonet
• Railed handguard - All flanks have 20mm Picatinny rail space
• Delta Ring handguard attachment method - Compatible with aftermarket M5 RAS style handguards
• 3-Position fire selector - SAFE-SEMI-AUTO by default, programmable via the Kestrel Basic ETU
• M4/M16 Flat trigger guard - Milspec configuration, push the detent in the front right to fold for gloved use
• 20mm Picatinny railed receiver - Ready for a red dot sight or scope, carry handle pre-installed
• Removable ghost ring rear iron sight 
• "A2" Finger ridged pistol grip - Accurate to the real M16A4, comfortable for most hand sizes
• Rotary adjustable HOP-up unit - Accessible when the charging handle is pulled and the mock bolt is locked back
• 6 Position sliding stock - Comfortable in various modern shooting stances
• Version 2 gearbox:
  • Enter & Convert™ quick change spring system
  • Steel spring guide
  • 8mm Ball bearing bushings
  • 18:1 Ratio steel gear set
• Kestrel Basic MOSFET/ETU functions:
  • Binary Trigger
  • 3-Round burst
  • Adjustable pre-cocking
  • Active braking
  • Low/high voltage cutoff
  • Low battery warning
• Kestrel Basic MOSFET/ETU programming instructions are available here
• Rear wired: Deans/T-Plug battery connector - Recommended battery: 7.4v 2600mAh 25C LiPo crane battery
• Compatible with M4/AR-15 AEG magazines - Spares are plentiful!

Package Includes

• Specna Arms SA-K02 ONE™ M4A1 AEG; Kestrel Basic ETU
• 300rnd High-capacity magazine