Trijicon ACOG ECOS FDE Green Crosshair Superb 4×32 Kit

Description

ECOS is Trijicon shorthand for Enhanced Combat Optical Sight, and it means the whole package in one box. The Trijicon ACOG ECOS FDE Green Crosshair is model TA31-D-100554: a 4×32 BAC prism with a green crosshair BDC reticle, an RMR Type 2 red dot above it, a set of backup iron sights, and an AC12033 quick release mount, all in flat dark earth.

Green Reticle, and Why the Package Exists

Reticle colour is the only thing separating this from the red version, and it is not a trivial choice. Green reads brighter to the human eye than red does at identical output, so in daylight and against open country the green crosshair is easier to find and hold. Red gives up some of that brightness in exchange for preserving your night adaptation. If your shooting is mostly in daylight, green is the better pick, and that is what the Trijicon ACOG ECOS FDE Green Crosshair gives you.

The rest of the package is about redundancy. The prism runs on fibre optics by day and tritium by night with no battery in it at all. The dot runs on its own cell. The backup irons need neither. Three systems, three separate zeros, and no single point of failure that takes the rifle out of action. That reasoning comes from agency procurement rather than from the range, which is why Trijicon sells it as a catalogued package instead of a parts list.

The quick release mount is the piece people underrate. The AC12033 is a lever mount rather than the TA51 thumbscrew adapter, so the whole assembly comes off the rail and goes back on without tools and returns to zero. On a rifle that gets cased, flown, transferred between shifts or stripped for cleaning, that is worth real money.

Trijicon ACOG ECOS FDE Green Crosshair Specifications

The prism is the standard TA31 body underneath the package: fixed 4x over a 32mm objective, 1.5 inches of eye relief, a 0.32 inch exit pupil, 36.8 feet of field of view at 100 yards, forged aluminium housing rated to 66 feet of submersion. The crosshair is calibrated for .223 and 5.56, with holdover stadia drawn for 55 grain ammunition from a 20 inch barrel.

The RMR supplied with the Trijicon ACOG ECOS FDE Green Crosshair is the Type 2, the revision where Trijicon reworked the electronics after early units struggled with slide mounted recoil impulses. Sitting on top of a prism it leads a comparatively gentle life. Trijicon retail for the complete package is 2,533 dollars, which covers both optics, the backup irons, the quick release mount, a lens pen and the adjuster cap lanyards.

• Trijicon model TA31-D-100554, ACOG ECOS package
• Magnification and objective: fixed 4x32mm
• Reticle: green crosshair, .223 and 5.56 BDC
• Illumination: fiber optics and tritium, no batteries in the prism
• Red dot: RMR Type 2 mounted above the prism
• Also included: backup iron sights
• Mount: AC12033 quick release mount
• Eye relief: 1.5 in. Exit pupil: 0.32 in
• Field of view: 36.8 ft at 100 yards
• Housing: forged aluminium, flat dark earth
• Submersion depth: 66 ft
• UPC 719307311824

Honest Notes on the Trijicon ACOG ECOS FDE Green Crosshair

This is a two and a half thousand dollar sighting package and most buyers do not need it. If you are not genuinely in a position where an optic failure has consequences, one good sight and a set of folding irons costs a third as much and does almost everything this does. The redundancy is the product, and redundancy only has value when the cost of being without a sight is high.

Three sights means three zeros, and the order matters. Start with the irons at twenty five yards so you have a baseline that needs no glass and no power, then set the magnified reticle at one hundred, then bring the dot up last at whatever distance you will actually use it. Record each result and note the ammunition, because changing loads will move all three by different amounts. Shoot five round groups rather than three, and keep the targets in a folder so you can see later whether a group has opened up. A slowly widening group is almost always a loose mount screw rather than a worn barrel, and it is much easier to spot on paper than at the bench.

Weight and bulk are the honest cost. The prism and mount alone are a little over a pound; add the dot, its bracket and the irons and there is a lot of mass sitting high and forward. This is a rack gun or a patrol rifle configuration, not something to build a lightweight carbine around.

Two smaller points. Height over bore on the dot is roughly three and a half inches, so close range impacts land well below it until you have learned the offset on paper. And if you are colour matching the flat dark earth to existing furniture, check the shade first: FDE varies noticeably between manufacturers, and the Trijicon ACOG ECOS FDE Green Crosshair will not necessarily match a different brand of stock.

Every Trijicon ACOG ECOS FDE Green Crosshair we list is current Trijicon production in the factory carton with both optics, the backup irons, the quick release mount and warranty paperwork. MAG5 Firearms is a family run FFL dealer in Collegeville, Pennsylvania, and optics ship direct to your door with no transfer needed.

See more rifle optics at MAG5 Firearms, or check the Trijicon TA31-D-100554 specification sheet from the manufacturer.