Daniel Defense® RIS III 12.5'' SA-P28 upgraded by Racek Custom Guns.

The RCG Prime series stands out for its high shooting accuracy, long-lasting internal parts, fast trigger response, and 1.7 J power output, with the added benefit of a quick spring change system.

RCG Prime offers you:

• An excellent balance between spring strength and performance in the 1.7 J to 2.6 J range, thanks to the easy-to-use ESA 2 quick spring change system
• Great shooting accuracy with a high-quality combination of hop-up chamber, inner barrel, bucking, and RCG nozzle play elimination
• High durability thanks to the robust Aether gearbox and CNC internal parts
• Fast trigger response ensured by the Dark Matter brushless motor combined with 16:1 gear ratio
• Low battery consumption
• ASTER II Bluetooth ETU by Gate
• 2x S-mag spring-fed magazines with speedloader included in the package

RCG Prime – a thoughtfully built setup down to the last detail

Durable Aether V2 gearbox

The durable Aether gearbox offers excellent longevity thanks to additional material in the front section, which is where standard V2 gearboxes most commonly crack. The gearbox has also been modified with a leveled front face for precise alignment of the hop-up chamber against the gearbox.

It is further equipped with high-quality, low-profile Retro Arms plain bearings, which provide long service life and precise gear alignment.

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Fast and high-quality gears

Precision 16:1 ratio gears from JINWANG x Specna Arms provide fast trigger response and are shimmed with minimal tolerance.

These JINWANG gears also offer improved tappet plate timing, preventing the nozzle from opening too early and helping the gun maintain stable performance.

Thanks to a custom-made brass cam, the tappet plate travel is extended, ensuring a highly sealed connection between the nozzle and hop-up bucking.

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Processor unit with Bluetooth connection to your smartphone

The RCG Prime is controlled by the ASTER II processor unit from Gate.

This unit offers Bluetooth connectivity to your phone via the GATE Control Station app. You get access to intuitive settings such as trigger sensitivity, pre-cocking, and shot statistics.

Air system with maximum air seal

To achieve maximum air efficiency, we used a selection of the best parts on the market:

• EPES duraluminum Extrafit cylinder head with PU 70 impact rubber, polished stainless steel nozzle tube, and eliminated play in the gearbox seating
• EPES duraluminum nozzle with double sealing and NiPTFE surface treatment for high smoothness
• EPES duraluminum piston head with AOE correction
• Retro Arms POM tappet plate for maximum durability
• Retro Arms polyamide piston reinforced with carbon fibers and a CNC spring steel rack
• Specna Arms stainless steel cylinder modified for longer rear tappet plate travel
• RCG reinforced 190% tappet plate spring

   

  

  

  

  

  

Powerful brushless motor

Unlike standard guns, the drivetrain is powered by the Dark Matter brushless motor from Specna Arms. This motor offers fast trigger response, excellent rate of fire, and very low battery consumption.

Compared to standard brushed motors, it also generates minimal heat.

After 3,600 shots, an 11.1V 1200mAh Li-Pol battery dropped from 100% charge to 29%, approximately from 12.55V to 11.35V, when using an AP110 spring.

Naturally, the gun also features a modified pistol grip for better motor compatibility, proper cable routing, and correctly adjusted motor height.

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RCG trigger guard for an improved look

The trigger guard is often an overlooked accessory, even though it forms an important part of the rifle’s silhouette. With the installed RCG trigger guard, the overall look of the gun is noticeably enhanced.

High shooting accuracy

The RCG Prime excels in shooting accuracy thanks to the use of high-quality parts and careful fine-tuning.

At the core of its accuracy is the Maxx Model M4A-PRO CNC hop-up chamber with precise TDC pressure adjustment for maximum consistency and repeatability. A major advantage of this chamber is the numbered adjustment wheel and the BB retention latch in the feed section, which prevents unnecessary BB loss when removing the magazine.

This setup is complemented by a combination of a Maple Leaf precision inner barrel and a Super Macaron hop-up bucking with 60 ShA hardness. Every barrel used in an RCG build undergoes our own quality inspection using a 6.01 x 100 mm gauge test. This ensures that only properly manufactured barrels are installed.

The hop-up bucking is also modified at the collar for smooth BB feeding.

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Special chamber inlet for even greater precision

The hop-up chamber is further fitted with a special inlet piece, which we designed based on our experience with HPA builds in our workshop to achieve even greater shooting precision.

The RCG inlet ensures precise connection between the chamber and the gearbox with zero play. The inner part of the inlet is reamed to a diameter 0.05 mm larger than the nozzle diameter. This perfectly stabilizes the nozzle, keeping the BB in the exact same position before each shot, which increases shooting precision.

In combination with the low-friction inlet material, RCG 190% tappet plate spring, and correctly aligned gearbox axis, this also eliminates mid-cap syndrome.

Final accuracy tuning

For maximum precision, additional modifications are made to completely eliminate play in the inner barrel and hop-up chamber.

The chamber receives complete elimination of both radial and axial play. This means it sits firmly in the receiver and cannot move or rotate undesirably, for example due to magazine movement. Pressing the chamber against the gearbox with O-rings also helps absorb piston impacts on the gearbox front face, extending gearbox life.

Thanks to our stabilization method, the inner barrel is not cut with grooves for O-rings, so there is no deformation of the inner bore. Instead, the inner barrel is firmly stabilized using O-rings in two points: in front of the chamber and at the modified mouth of the outer barrel.

Receiver tuning to perfection

In our workshop, we fine-tune every rifle down to the last detail, and RCG Prime is no exception. The goal is to eliminate all factory play and imperfections.

Correct gearbox alignment

Proper gearbox alignment is the foundation of stable performance and accurate shooting. Thanks to our own specially designed tools and procedures, the gearbox axis is adjusted with a tolerance of up to 0.05 mm.

Vertical and lateral axis alignment is carried out entirely inside the receiver, so the external appearance remains untouched.

Outer barrel alignment and fitment

Most AR15-style airsoft guns have a significant difference in the seating diameter of the outer barrel in the upper receiver. This causes the outer barrel to sit off-axis, and when the handguard barrel nut is tightened, it can also rotate, which affects the radial positioning of the hop-up chamber.

To solve this, the upper receiver barrel seat is shimmed, allowing the outer barrel to fit firmly in the receiver. The radial alignment of the outer barrel is then adjusted for proper hop-up chamber seating.

When reinstalling the handguard, its seating is also checked. Any play found is removed.

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