Trijicon TA31-D 100553 ACOG ECOS | 4x32mm | FDE | .223

The Trijicon ACOG ECOS (TA31-D-100553) is a dual-sighting optic that combines a magnified 4x ACOG with a mounted RMR Type 2 red dot. It provides a magnified aiming option and a quick-acquisition red dot in a single package for users who need both precision and rapid target acquisition. The sight is calibrated for .223 and is built with fiber optics and tritium illumination for day/night use.

Applications include precision shooting at intermediate distances and close-quarters target acquisition where a fast, non-magnified point of aim is preferred. The ECOS package is also suitable for field use where a rugged, waterproof optic and quick-release mount are required.

Product Specifications

• The magnification is 4x.
• The objective size is 32mm.
• The reticle is an illuminated Red Crosshair .223 BDC.
• The illumination source is Fiber Optics & Tritium.
• The optic is calibrated for .223.
• The eye relief is 1.50 inches.
• The field of view at 100 yards is 36.8 feet.
• The exit pupil measures 8 mm.
• The overall length is 6.2 inches.
• The weight is 15 oz.
• The adjustment value is 1/2 MOA per click.
• The mount type is a Quick Release mount and the package includes a quick release mount.
• The finish is Flat Dark Earth.
• The package includes a 3.25 MOA RMR Type 2 LED Red Dot mounted to the ACOG and back-up iron sights.
• The UPC is 719307311817.

The ACOG ECOS blends a fixed 4x magnifier with a compact RMR Type 2 red dot to give users two practical aiming solutions in one durable housing. Its illumination system supports low-light use without batteries for the ACOG reticle, and the included RMR provides battery-powered rapid engagement when needed. For shooters who require a versatile optic that performs in both deliberate and rapid scenarios, this ECOS package delivers proven optical clarity and battlefield-proven durability in a civilian-legal form.