Rossi M4 Sentinal Zeta Black

Construction & Design

• Durable Polymer Build: Lightweight polymer upper/lower receiver and buffer tube help reduce weight without sacrificing sturdiness

• Modular Handguard: Polymer 8.5″ or 10.5″ M‑LOK handguard supports various attachments like grips, lights, and lasers

• Metal Touchpoints: Metal flash hider, fire selector, mag release, sling mount, and sights improve durability

Internals & Performance

• Gearbox: V2 gearbox equipped with:

  • 18:1 steel gears

  • Steel-tooth piston (14.5 teeth)

  • 8 mm bearing bushings

  • Quick-detach (QD) spring guide for fast FPS swaps

• ETU & Active Brake: Electronic Trigger Unit Ver.1 delivers quick response in semi/full-auto modes

• Barrel & Hop-Up:

  • Precision 6.02 mm inner barrel (~230 mm on 8.5″, ~300 mm on 10.5″)

  • Rotary/adjustable hop-up ensures trajectory control

• Velocity: Typically around 300–320 fps with 0.20 g BBs—compliant with most UK field limits

Handling & Ergonomics

• Compact Handling:

  • Length: ~700–780 mm (stock extended)

  • Weight: ~1.9–2.0 kg (without battery)

• Adjustability: Crane stock for length customization and internal battery storage; low-profile flip-up sights for quick aiming

• Fire Selector: Ambidextrous safe / semi / full-auto modes

Extras & Compatibility

• Magazine: Includes a 300‑round polymer hi-cap magazine (or up to 350 rnd per some listings)

• Battery: Uses 7.4 V LiPo stick (mini‑Tamiya or Deans—not included)

• Spring Swapping: QD guide enables compliance with field FPS limits.

Ideal Use & Upgrades

• CQB & Mid‑Range Ready: Compact size, agile weight, and reliable internals make it ideal for versatile gameplay.

• Upgrade-Friendly: Modular handguard and solid gearbox internals allow for easy upgrades — optics, grips, improved inner barrels, suppressors.

• Budget-Smart: Offers strong baseline performance for beginners and experienced players without overspending.

Quick Specs Summary