Trijicon ACOG ECOS FDE Red Crosshair Superb 4×32 Combo

Description

ECOS stands for Enhanced Combat Optical Sight, and it is Trijicon assembling everything at once. The Trijicon ACOG ECOS FDE Red Crosshair is model TA31-D-100553: the 4×32 BAC prism with a red crosshair BDC reticle, an RMR Type 2 red dot on top, a set of backup iron sights, and an AC12033 quick release mount, all finished in flat dark earth.

Three Sighting Systems in the Trijicon ACOG ECOS FDE Red Crosshair Package

Work through the layers, because that is what you are buying. The ACOG gives you 4x magnification with an etched reticle lit by fibre optics and tritium, and it has no battery at all. The RMR Type 2 on top gives you an unmagnified dot for close work, on its own independent cell. The backup iron sights fold into the package as a third layer that needs neither glass nor power. If any one of them fails, two others are already zeroed and waiting.

That redundancy is the entire design argument. A low power variable is one system: if the tube takes a hit, you have nothing. Here the failure of any single component leaves the rifle fully usable. It is the sort of reasoning that comes from military procurement rather than from the range, which is why this exists as a catalogued package rather than as parts you assemble yourself.

The quick release mount is the other meaningful difference from the standard combos. The AC12033 is a lever mount rather than the TA51 thumbscrew, so the whole assembly comes off the rail and goes back on without tools and without losing zero. On a rifle that gets cased, flown or handed between people, that matters more than it sounds.

Trijicon ACOG ECOS FDE Red Crosshair Specifications

The prism itself is the standard TA31 body: fixed 4x over a 32mm objective, 1.5 inches of eye relief, a 0.32 inch exit pupil and 36.8 feet of field of view at 100 yards. Housing is forged aluminium, rated to 66 feet of submersion, finished in flat dark earth rather than black. The reticle is a red crosshair calibrated for .223 and 5.56, dual illuminated by fibre optics in daylight and tritium after dark.

The RMR Type 2 supplied with the Trijicon ACOG ECOS FDE Red Crosshair is the revision where Trijicon reworked the electronics after early units struggled with slide mounted recoil. On top of an ACOG it has an easy life. Trijicon retail for the complete package is 2,533 dollars, which also covers the backup iron sights, a lens pen, adjuster cap lanyards and the quick release mount.

• Trijicon model TA31-D-100553, ACOG ECOS package
• Magnification and objective: fixed 4x32mm
• Reticle: red crosshair, .223 and 5.56 BDC
• Illumination: fiber optics and tritium, no batteries in the prism
• Red dot: RMR Type 2 mounted above the ACOG
• 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 719307311817

Plan the zeroing session before you go. Three independent aiming systems means three separate zeros, and the order matters: start with the irons at twenty five yards so you have a baseline that needs no power and no glass, then set the magnified prism at one hundred, then bring the dot up last at whatever distance you expect to use it. Record each one. Shoot five round groups rather than three, and note which ammunition you used, because switching loads will move all three by different amounts. An afternoon spent doing this properly is what turns a very expensive collection of parts into a rifle you can actually trust in any of its three configurations.

Honest Notes on the Trijicon ACOG ECOS FDE Red Crosshair

The price is the honest starting point. At Trijicon retail this is a two and a half thousand dollar sighting package, more than most complete rifles and more than many people spend on a rifle and optic together. The component parts add up to roughly the same money bought separately, so it is not a markup for the box, but it is still a serious outlay. If redundancy is not something you actually need, a single good optic and a set of irons costs a third as much.

Weight and bulk are the second cost. An ACOG with mount is already a little over a pound; adding the RMR, its mount and the backup irons puts more mass high and forward on the rifle. This is a duty and range configuration rather than something you carry all day in the hills. This package suits a gun that lives in a rack or a vehicle and gets used hard, not a lightweight build.

Height over bore on the RMR is worth a range session. Sitting on top of the ACOG the dot is roughly three and a half inches above the barrel, so at close distance your rounds land well below it. It is entirely predictable once you have shot it at five, ten and twenty five yards on paper, but it is more pronounced than on a normal flat top mounted dot and it catches people out the first time.

Everything true of any ACOG applies here too. Eye relief is 1.5 inches and the eye box is unforgiving, so it rewards a repeatable cheek weld. Reticle brightness is automatic rather than adjustable. And if you are matching the flat dark earth to existing furniture, check the shade first, because FDE varies between manufacturers more than people expect.

Every Trijicon ACOG ECOS FDE Red 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-100553 specification sheet from the manufacturer.