polarstar f2 begadi neptune pro alignment kit v2 5

Version 2.5 of the hop-up alignment system, designed specifically for SR25 DMR HPA (Designated Marksman Rifle) replicas using:

• PolarStar F2 engine (dual-solenoid HPA engine optimized for long-range precision configurations).
• BEGADI NEPTUNE PRO chamber (high-precision hop-up chamber designed for DMR setups, featuring micrometric adjustment and excellent support for heavy buckings).

This kit ensures perfect alignment between the F2 nozzle and the Neptune PRO chamber, eliminating any lateral play and maximizing shot consistency for long-range precision (up to 70m+). Optimized for long V2.5 gearboxes and compatible with ICS lowers, making it ideal for professional DMR builds.

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Compatibility

Component	Compatibility
HPA Engine	PolarStar F2 (SR25 configuration)
Hop-up Chamber	BEGADI NEPTUNE PRO
Base Replica	SR25 DMR
Gearbox	Long V2.5 / ICS SPLIT

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What the kit includes

• Reinforced rear clip for mounting on a long V2.5 gearbox using the rear pin or fixed stock.
• Extended base with housing for M3 inserts (brass recommended for durability).
• Wide side clip for routing the HPA tube/line in DMR configurations.
• Front locking top cap designed specifically for the Neptune PRO chamber.
• Rear plate with mounting point for an M5 screw (extra reinforcement for heavier builds).

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Installation and adjustment

1. Printing and preparation

• Print the parts with 70–90% infill (extra rigidity for DMR builds).
• Lightly sand internal areas and contact surfaces for a perfect fit.
• Apply dry lubricant or lithium grease to moving areas for long-term builds.

2. Installation in the replica

• Insert the extended base into the ICS lower and install the M3 inserts.
• Mount the rear clip aligned with the long rear pin of the V2.5 gearbox.
• Install the Neptune PRO chamber with a precision inner barrel (6.01–6.03 mm recommended); the top cap locks the assembly while maintaining millimetric alignment.
• Route the F2 HPA line through the reinforced side clip (compatible with 4–6 mm tubing).

3. Final fixation and DMR calibration

• Secure the rear plate using an M5 screw and large washer for maximum stability.
• Configure the PolarStar F2 in semi-auto DMR mode (1.5–2.0 Joules, 80–120 PSI).
• Verify alignment using 0.32 g+ BBs and adjust the Neptune PRO micrometric hop-up for a flat trajectory at 50–70 m.

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Required components (not included)

• 4× M3 × 4.2 mm threaded inserts (brass recommended for DMR builds)
• 4× M3 × 10 mm SHCS screws (slightly longer for V2.5 gearbox)
• 1× M5 × 16 mm screw + washer (for rear plate)

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Lower receiver recommendations

Compatible with metal ICS lowers (recommended for SR25 DMR builds).

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

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3D printing parameters

• Approximate print time: ~2 h (extended design for V2.5)
• Recommended material: PLA+ or PETG (better durability for DMR builds)
• Layer height: 0.10 mm – 0.15 mm
• Infill: 70–90% (critical rigidity for precision)

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Manuals

Specific SR25 DMR manuals are available in the Manuals section of the website or on the project’s Discord server.