redline n7 milsim g2 begadi neptune pro alignment kit

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

• Redline N7 Milsim G2 engine (second-generation compact HPA engine optimized for milsim configurations with excellent pressure control and response).
• Begadi Neptune Pro chamber (high-precision hop-up chamber with micrometric adjustment system and geometry optimized for HPA).

This system ensures perfect centering between the N7 G2 nozzle and the Neptune Pro chamber, eliminating BB feeding variations and maximizing pneumatic flow efficiency in high-performance builds.

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Compatibility

Component	Compatibility
HPA Engine	Redline N7 Milsim G2
Hop-up Chamber	Begadi Neptune Pro
Base Replica	M4 AEG
Gearbox	V2 / ICS SPLIT

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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 Neptune Pro.
• 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 contact areas to achieve a clean fit.
• Apply dry lubricant or wax on sliding surfaces if frequent maintenance is expected.

2. Installation in the replica

• Insert the base into the lower and install the M3 inserts.
• Mount the rear clip aligned with the rear pin or the stock mounting point.
• Install the Neptune Pro chamber with the inner barrel; the top cap locks the assembly while keeping the barrel perfectly centered.
• Route the N7 G2 HPA line through the side clip to prevent sharp bends.

3. Final fixation

• Secure the rear plate using an M5 screw with washer for maximum rigidity.
• Verify that the Redline N7 nozzle enters the Neptune Pro chamber perfectly centered without lateral play.
• Perform dry feeding tests and adjust the Neptune Pro micrometric hop-up according to your BB weight and bucking.

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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 your own 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:
https://lab.sychev.xyz/prodcuts?q=universal

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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.