Trijicon ACOG TA31ECOS Review


TA31ECOS front left


The Trijicon TA31ECOS is the battle-proven TA31 4X32 ACOG fitted with two back-up aiming options. The first is the Trijicon RMR rear mounted reflex sight with a 3.25 or 4 MOA red dot reticle (the latter results in the designation TA31ECOS-G). This site is battery operated and waterproof to 11 meters.

Trijicon ACOG TA31ECOS

Trijicon ACOG TA31ECOS

The RMR red dot sight gives very rapid target acquisition and engagement at short to medium ranges. In the unlikely event that your Trijicon RMR sight is non-operational, the TA31ECOS features a built in aperture rear sight and front post sight that can be repositioned on either side of the unit to cater for left or right handed shooters. The TA31 ECOS itself features the Bindon Aiming Concept with a fiber-optic illuminated crosshairs reticle incorporated into a ballistic aiming ladder calibrated for 62 grain 5.56X45mm ammunition. The ACOG ECOS is supplied with an A.R.M.S. dual throw lever quick-detach mount to suit MIL-STD 1913 Picatinny rails. This can easily be removed to make the sight suitable for carry handle mounting. The TA31ECOS comes in Dark Earth to suit the most likely theatres of operation for US Forces.

TA31ECOS reticle

TA31ECOS reticle ballistically calibrated to 5.56X45mm 62 grain ammunition


Magnification 4x
Objective Size 32
Bullet Drop Compensator Yes
Length (In) 6.2
Weight (oz) 15
Illumination Source Fiber Optics & Tritium
Reticle Pattern Crosshair
Day Reticle Color Red
Night Reticle Color Red
Calibration 0.223
Eye Relief 1.5
Exit Pupil 8
Field of View (Degrees) 7
Field of View @ 100 yards (ft) 36.8
Adjustment @ 100 yards (clicks/in) 2
Mount A.R.M.S. #19LD
Mount Comes With A.R.M.S. #19LD
Housing Material Forged Aluminum
Available Options:
TA31ECOS: Trijicon ACOG 4×32 Dark Earth Brown Scope, Dual Illumination Red Crosshair Reticle w/ 3.25 MOA RMR Sight
TA31ECOS-G: Trijicon ACOG 4×32 Dark Earth Brown Scope, Dual Illumination Green Crosshair Reticle w/ 4.0 MOA RMR Sight

The TA31ECOS also includes:

1 3.25 or 4.0 MOA RMR™ LED Red Dot Sight mounted to ACOG
1 A.R.M.S.® Throw Lever Mount
1 Set of backup Iron Sights
1 Lenspen (TA56)
1 Trijicon Logo Sticker (PR15)
1 ACOG Manual
1 Warranty Card

Check the price of the TA31ECOS at Brownells, a name you can trust.

We hope you find this video on installing an AR aftermarket trigger system of interest:

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