Rossi M4 Sentinel 9" BETA (Black)

Construction & Aesthetics

• Polymer Build: Both upper and lower receivers, along with the handguard, are made from durable polymer - keeping weight low while retaining robustness

• Handguard Design: Features a 9″ polymer handguard with Picatinny rails on all four sides, styled after Daniel Defence - ideal for mounting a wide range of accessories

• Metal Components: Externally, high-wear parts like flash hider, fire selector, mag release, sling point and sights are metal - delivering durability in key areas

Gearbox & Internals

• Version 2 Gearbox packed with quality components:

  • 18:1 steel gearset

  • Steel-tooth piston (14.5 teeth)

  • 8 mm bearing bushings

  • Quick-change (QD) spring guide

• Trigger System: Equipped with ETU (Ver.1) featuring active brake and MOSFET protection, enabling crisp semi/full-auto firing

• Barrel & Hop-Up: 6.02 mm precision inner barrel (~260 mm long) paired with a rotary hop-up for quick accuracy adjustments

• Performance: Produces around 310 fps with 0.20 g BBs - suitable for most UK field limits

Handling & Ergonomics

• Length & Weight: Compact CQB-oriented profile - length adjusts from ~700 to 780 mm; weight sits about 2.2 kg - balanced and maneuverable

• Stock & Sights: Adjustable crane-style stock and low-profile flip-up sights included for versatile field use

• Battery Setup: Standard mini-Tamiya connector; 7.4 V LiPo recommended (not included)

Extras & Magazines

• Magazine: Ships with a 300-round polymer hi-cap magazine

• Quick Spring Change: QD system allows fast compliance with field FPS regulations

Quick Reference Table

• Feature
  Details
• Construction
  Polymer receiver & 9″ Picatinny polymer handguard
• Gearbox
  V2 w/ 18:1 steel gears, steel piston, 8 mm bearings
• Trigger & Electronics
  ETU Ver.1 w/ active brake & MOSFET
• Barrel & Hop-Up
  6.02 mm × ~260 mm, rotary hop-up
• FPS
  ~310 fps (0.20 g)
• Fire Modes
  Safe / Semi / Full-auto
• Magazine
  300-round polymer hi-cap
• Stock & Sights
  Crane stock; flip-up polymer sights
• Weight & Length
  ~2.2 kg; 700-780 mm
• Battery Plug
  Mini-Tamiya (LiPo 7.4 V recommended)

Verdict

The Rossi Sentinel BETA blends lightweight handling with strong internals and tactical accessory readiness. With key upgrades like the Picatinny quad rails, ETU + MOSFET, and QD spring guide, it's a well-rounded option for CQB and mid-range play. Its price point also makes it an accessible choice for players seeking a durable, customizable AEG platform.