blackdraft phoenix begadi neptune pro alignment kit v2

Version 2.1 of the hop-up alignment system, designed for M4 AEG HPA replicas using:

• Blackdraft Phoenix engine (compact and affordable HPA engine with an excellent price-to-performance ratio).
• Begadi Neptune Pro chamber (high-precision hop-up chamber with micrometric adjustment and geometry optimized for HPA systems).

This kit ensures solid and precise alignment between the Phoenix nozzle and the Neptune Pro chamber, maximizing feeding consistency and taking full advantage of the direct airflow from the HPA engine for improved compression and long-range shot grouping.

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Compatibility

Component	Compatibility
HPA Engine	Blackdraft Phoenix M4 HPA Engine
Hop-up Chamber	Begadi Neptune Pro
Base Replica	M4 AEG
Gearbox	V2 / ICS SPLIT (explicitly ICS compatible)

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What the kit includes

• Rear clip for mounting via rear pin or fixed stock.
• Base with housing for M3 inserts (optional brass).
• Side clip for routing the HPA tube/line.
• Front locking top cap designed specifically for the Neptune Pro geometry.
• Rear plate with mounting point for an M5 screw (additional reinforcement).

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Installation and adjustment

1. Printing and preparation

• Print the parts with 65–80% infill.
• Lightly sand internal areas and contact surfaces for a clean fit.
• Apply dry lubricant or wax on sliding areas if you want easier maintenance.

2. Installation in the replica

• Insert the base into the lower and install the M3 inserts in their housings.
• Mount the rear clip aligned with the rear pin or stock mounting point.
• Install the Begadi Neptune Pro chamber with the inner barrel; the top cap locks the assembly while keeping the barrel perfectly centered.
• Route the Blackdraft Phoenix HPA line through the side clip to prevent bends.

3. Final fixation

• Secure the rear plate with an M5 screw and washer for maximum rigidity.
• Verify that the Phoenix nozzle enters the Neptune Pro chamber perfectly centered without lateral play.
• Adjust the Neptune Pro micrometric hop-up according to BB weight and field conditions.

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Required components (not included)

• 4× M3 × 4.2 mm threaded inserts
• 4× M3 × 8 SHCS screws

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Lower receiver recommendations

For maximum rigidity it is recommended to use the ICS metal lower receiver.

If you prefer to print the lower part, the following Gearbox V2 Lower “Universal Lower Part” models are compatible:

• Version 3
• Version 4.2
• Version 4.3 MTW

You can find them HERE.

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3D printing parameters

• Approximate print time: ~1 h 30 min
• Recommended material: PLA+
• Layer height: 0.10 mm – 0.15 mm

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Manuals

Installation and adjustment manuals are available in the Manuals section of the website or on the project’s Discord server.