M55 SABR

The M55 SABR is an infantry battle rifle used by the UNSC Marine Corps, Navy, and First Encounter Assault Recon division. It is a derivative of the M55 SCAR platform, designed for precision shooting at longer ranges than a standard assault rifle or carbine.

Overview
The M55 Superior Adaptive Battle Rifle is a selective fire, gas-operated, fully ambidextrous bullpup battle rifle derived from the M55 SCAR. The trigger and safety system were, as in the parent design, retained from the M37 assault rifle, consisting of a Spz-kr type progressive trigger (pulling the trigger halfway produces semi-automatic fire, pulling the trigger all the way to the rear produces three-round burst fire) and a safety mechanism (cross-bolt, button type), located immediately above the hand grip.

The SABR is fed from box magazines with a 30-round cartridge capacity using polymer-cased, high-pressure 7.62x51mm ammunition. The magazine catch/release button is installed symmetrically in the pistol grip, in front of the magazine well. The SABR retains the "flush-lock" magazine well of the SCAR, requiring the magazine to be pulled out manually once the catch has been pressed.

The SABR has a heavy 621mm barrel, giving it an effective range of 900 meters and a maximum range of 1,200 meters. It also features a built-in electronics suit that includes a smart-linked electronic targeting system and a digital ammunition counter. The carry handle features flip-up iron sights and a VCOG-A2 2x magnification sight.

Variants
SABR-X: prototype SABR issued to Staff Sergeants Avery Johnson and Nolan Byrne, as well as colonial militia sharpshooters Jacob Critchley and Wallace Jenkins in 2525. Adopted as the M55 SABR Mod 1 in 2527.

SABR Mod 2: improved version issued in 2548 alongside the SCAR Mod 2.