polarstar f1 maxx model alignment kit v2 5 sr25 dmr

Version 2.5 of the hop-up alignment system, designed specifically for SR25 DMR HPA (Designated Marksman Rifle) replicas with long V2.5 gearboxes.
This configuration combines the PolarStar F1 engine with the MAXX MODEL hop-up chamber to achieve precise nozzle alignment in long-range, high-precision setups.

Compatible with ICS lowers and V2.5 long gearboxes, making it ideal for DMR builds using M14x1 LH outer barrel threads and 550–700 mm inner barrels.

This kit optimizes the feeding of heavy BBs (0.32g–0.43g) typical of DMR configurations, eliminating inconsistencies caused by misalignment in long gearbox HPA systems.

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Compatibility

Component	Compatibility
HPA Engine	PolarStar F1 SR25 DMR
Hop-up Chamber	MAXX MODEL
Base Replica	SR25 DMR
Gearbox	V2.5 Long / ICS SPLIT

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What the kit includes

• Reinforced rear clip for mounting on long V2.5 gearbox.
• Extended base with housing for M3 inserts (brass recommended for DMR builds).
• Side clip for routing the HPA line in long SR25 configurations.
• Front locking top cap designed specifically for MAXX MODEL chamber geometry.
• Rear plate with dual mounting points for M5 screws (extra rigidity for DMR setups).

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Installation and adjustment

1. Printing and preparation

• Print with 80–100% infill (extra rigidity required for DMR builds).
• Lightly sand internal surfaces to ensure a precise fit inside the long gearbox.
• Apply dry lubricant on sliding surfaces for easier maintenance.

2. Installation in the SR25

• Install the extended base in the ICS lower or compatible V2.5 receiver.
• Mount the rear clip using the reinforced rear gearbox pin.
• Install the MAXX MODEL chamber with a long inner barrel (550–700 mm); the top cap keeps the assembly perfectly centered.
• Route the PolarStar F1 HPA line through the extended side clip.

3. Fixation and DMR testing

• Secure the assembly using 2× M5 screws with washers for maximum structural stability.
• Verify that the F1 nozzle aligns perfectly with the MAXX MODEL chamber when feeding heavy BBs.
• Configure the F1 engine for DMR velocity ranges (95–120 m/s) and test consistency at 50+ meters.

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Required components (not included)

• 6× M3 × 4.2 mm threaded inserts (2 extra for V2.5 length)
• 6× M3 × 8 SHCS screws
• 2× M5 × 10 screws (for rear plate)

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Lower receiver recommendations

Compatible with original ICS metal lower receivers (recommended for DMR builds).

Printable alternatives for Gearbox V2.5 Lower “Universal Lower Part” adapted for SR25:

• Version 3 (long gearbox adapted)
• Version 4.2 (long gearbox adapted)
• Version 4.3 MTW (reinforced version)

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

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3D printing parameters

• Approximate print time: ~2 h (longer parts for SR25)
• Recommended material: PLA+ or PETG (better durability for DMR builds)
• Layer height: 0.10 mm – 0.15 mm
• Infill: 80–100% (critical rigidity for long platforms)

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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.