polarstar f2 maxx model alignment kit v2 5 sr25 dmr

Version 2.5 of the hop-up alignment system, designed specifically for SR25 DMR HPA replicas (long V2.5 gearbox) using:

• PolarStar F2 engine (dual-solenoid HPA engine optimized for DMR configurations with precise control of pressure and air volume).
• MAXX MODEL chamber (high-precision hop-up chamber with fine adjustment, widely used in DMR builds for consistent performance with medium–heavy BB weights).

This kit ensures perfect centering between the F2 nozzle and the MAXX MODEL chamber in long V2.5 gearboxes, eliminating lateral variations and maximizing stability in long-range semi-automatic shots. Fully compatible with ICS lowers and split gearbox systems.

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Compatibility

Component	Compatibility
HPA Engine	PolarStar F2 SR25
Hop-up Chamber	MAXX MODEL
Base Replica	SR25 DMR
Gearbox	Long V2.5 / ICS SPLIT

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What the kit includes

• Reinforced rear clip for mounting using the rear body pin or fixed stock (adapted for long gearboxes).
• Extended base with housing for M3 threaded inserts (brass recommended for DMR builds).
• Side clip for routing the HPA line in SR25 configurations.
• Front locking top cap specific for the MAXX MODEL chamber in V2.5 geometry.
• Rear plate with mounting point for an M5 screw (additional structural reinforcement).

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Installation and adjustment

1. Printing and preparation

• Print the parts with 70–85% infill (extra rigidity for DMR builds).
• Lightly sand internal areas and contact surfaces for a precise fit.
• Apply dry lubricant on moving areas to simplify maintenance in precision builds.

2. Installation in the replica

• Insert the extended base into the ICS lower receiver and install the M3 threaded inserts.
• Mount the rear clip aligned with the rear pin of the long V2.5 gearbox.
• Install the MAXX MODEL chamber with a DMR inner barrel; the top cap locks the assembly while maintaining perfect alignment.
• Route the PolarStar F2 HPA line through the side clip to ensure a clean, friction-free path.

3. Final fixation

• Secure the rear plate using an M5 screw and washer for maximum stability in semi-automatic fire.
• Verify correct centering of the F2 nozzle inside the MAXX MODEL chamber (critical when using 0.32g+ BBs).
• Configure the F2 at low–medium pressures (60–100 PSI) for DMR control and test consistency at 50 m+.

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Required components (not included)

• 4× M3 × 4.2 mm threaded inserts (brass recommended).
• 4× M3 × 8 SHCS screws.
• 1× M5 × 12 mm screw + washer (for the rear plate).

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Lower receiver recommendations

Compatible with the original ICS metal lower receiver, recommended for SR25 DMR builds due to its rigidity.

If you prefer a printable option, the following Gearbox V2 Lower “Universal Lower Part” models are compatible with long V2.5 gearboxes:

• Version 3
• Version 4.2
• Version 4.3 MTW

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

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3D printing parameters

• Approximate print time: ~1 h 45 min (larger V2.5 parts)
• Recommended material: PLA+
• Layer height: 0.10 mm – 0.15 mm
• Infill: 70–85% (DMR rigidity)

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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.